BNWAT02 Showers: market projections and product …efficient-products.ghkint.eu/spm/download/document/id/962.pdf · BNWAT02 Showers: market projections and product ... 1999 2004 2009

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First created: 11/03/2011 Updated: http://efficient-products.defra.gov.uk Last reviewed: 11/03/2011 1 of 49 0845 600 8951

BNWAT02 Showers: market projections and product details

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This Briefing Note and referenced information is a public consultation document and will be used to inform Government decisions. The information and analysis forms part of the Evidence Base created by Defra‟s Market Transformation Programme.

1 Introduction

The Market Transformation Programme (MTP) is designed to transform the market to

increase uptake of sustainable products, reducing the operational environmental impact of

products.

The main ways of doing this are:

Effective regulation;

Better information for consumers;

Incentives to change purchasing trends and habits; and

Policies on procurement, planning, and construction activity.

The MTP has an important role in providing the evidence underpinning policy development.

In its widest sense the MTP covers electrical, heating, lighting, and water using products and

appliances in the domestic sector. The MTP is also tackling energy using products in the

commercial/non household sector.

It is advisable to read this briefing note in conjunction with BNWAT03 Baths: market

projections and product details as the MTP strategy targets personal bathing as a whole.

BNWAT03 sets out useful information to support a transition from high volume baths to

smaller volume models, in the context of continuing to promote showering as an alternative

to bathing. The strategic aim is to reduce the overall demand for water and carbon

emissions currently associated with personal washing.

This briefing note is for showers as part of the domestic water using products element of the

MTP. The information in this note is for England and Wales as Defra and Welsh Assembly

Government actions and policies may not be applicable in Scotland and Northern Ireland.

The supplementary note BNWAT08: Modelling projections of water using products contains

more information on the water sector MTP modelling process and assumptions. It is

recommended that is referred to when using this briefing note.

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1.1 Water sector MTP goal

The purpose of the MTP is to create opportunities that will transform the market towards

more sustainable products. The goal of this MTP is to significantly increase the market

share of the most sustainable shower product types, by elevating sales of these products

above current levels, and above what is projected under the Reference Scenario. Detailed

information on different types of shower is presented in Appendix A.

The current trend is for a rapidly increasing number of customers to own showers that

provide high flow-rate, which together with higher frequency of use, results in water and

energy use by showers often being greater than for baths1. The MTP aim to slow, halt, or

reverse this trend.

1.2 Purpose of the briefing note

The overall purpose of this briefing note is to inform and advise Government and other policy

makers and stakeholders of the environmental benefits of implementing policies and taking

actions to actively transform the market.

The projections in the MTP define three scenarios, based on assumptions on sales and

stock levels of products: Reference, Policy, and Earliest Best Practice (EBP) and the

environmental implications of each. These scenarios reflect what is possible if a set of

actions is taken. These scenarios should not be considered to be forecasts. These

projections are for households in England and Wales only.

Other analysts may assess and use the MTP assumptions as a basis on which to develop

their own consumption forecasts. For example, water industry users may use this

information to benchmark their individual forecasts and assumptions. Supporting information

on the product types, historical stock levels, product specifications and testing, and

associated technical issues are included within appendices. More information on how water

is used in different buildings is available in briefing note BNWAT06 Water use in new and

existing buildings”.

1 United Utilities (2007). Water and Energy Efficient Showers. Project Report.

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1.3 Content of the briefing note

This briefing note contains the following information:

Section Information

1 Introduction

2 Shower market scenarios: Base year and scenario assumptions, projection outputs, scenario actions

3 Environmental benefits: water and energy consumption per scenario

4 Recommendations to progress the water sector MTP

Appendix A

Product details

A.1 Shower product definitions

A.2. Volume per use

A.3 Shower lifespan

A.4 Shower product innovations

Appendix B

The current market

B.1 Showering as a micro-component of water demand

B.2 Existing shower ownership

B.3 Applicability of water efficient models per building type

Appendix C

Transforming the market

C.1 The impact of the globalised market on England and Wales

C.2 Factors that influence consumer use and uptake of showers

Appendix D

WC Technical specification and testing

D.1 Regulations

D.2 Standards

D.3 Performance criteria and tests

D.4 Impact of water supply systems on shower performance

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2 Shower market scenarios

2.1 Future market scenarios

The three standard scenarios presented in this briefing note are in-line with those used

elsewhere in the wider MTP. The scenarios are used to project and demonstrate the

potential impacts of the market transformation strategies, actions and targets. These are:

The “Reference Scenario”: This is a projection of what is likely to happen without any

new policy intervention. The scenario is based on current trends, technology

developments and policies that are already in place.

The “Policy Scenario”: This scenario estimates what could be achieved through an

ambitious but feasible set of policy measures if the agreement of all stakeholders was

obtained.

The “Earliest Best Practice Scenario” (EBP): This is a projection of what could happen

if the best available products and technologies were adopted, coupled with ambitious

Government policies.

The Policy and EBP scenarios assume that the actions required to ensure the successful

implementation of the policies are delivered. The impact of these policy combinations is

translated in the MTP model as projected sales and stock levels (ownership) of each of the

product sub-types. Further information on this is available in BNWAT08 Modelling

projections of water using products.

2.2 Summary of model outputs

Figure 2.1 shows the future water consumption projections for showering under the three

scenarios until 2030. Water consumption increases in all three scenarios which reflect the

shift in bathing patterns. Figure 2.2 shows the water consumption for the model outputs for

showers and baths combined to reflect the overall trend in bathing. Tables 2.1 and 2.2

quantify the consumption data at key time intervals.

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Figure 2.1 Shower water consumption projections for England and Wales

Shower water consumption - England & Wales

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Table 2.1 Shower water consumption projections for England and Wales

Year 2010 2015 2020 2025 2030

Ml/year: Reference 325,577 352,531 402,945 442,126 478,059

Ml/year: Policy 325,577 357,023 415,270 464,694 512,972

Ml/year: EBP 325,577 345,643 369,431 384,115 405,081

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Figure 2.2 Total bathing (shower and bath) water consumption for England and Wales

Total bathing and showering water consumption - England & Wales

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Table 2.2 Total bathing water consumption projections for England and Wales

Year 2010 2015 2020 2025 2030

Ml/year: Reference 825,502 858,641 916,873 965,096 1,007,713

Ml/year: Policy 825,502 818,487 853,847 883,333 912,854

Ml/year: EBP 825,502 806,193 802,706 791,091 788,497

2.3 Policies underpinning the Scenarios

The two key policies that are expected to influence sales and thus stocks of different volume

showers in the future under the Reference Scenario are:

The Code for Sustainable Homes (CSH), or other similar sustainability standard for

new homes; and

The Building Regulations.

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However, under the more ambitious Policy and EBP Scenarios it is assumed that individual

stakeholders will respond to these policies more rigorously, either due to successful

influencing strategies or a reversion to more regulatory based implementation.

Under the Policy Scenario the same drivers exist but there is a greater emphasis on

providing developers, builders and retailers with better information on using lower flow

showers to meet the CSH and Building Regulations. It assumes more effective

implementation and accelerated take up of the more sustainable products. Additional

policies will contribute to the direction driven by CSH and Building Regulations:

Green Deal;

EU Green Procurement Policy;

Ongoing activities of organisations such as Waterwise; and

Developer/Housing Association policies on Smart Refurbishment.

Product labelling.

The policies outlined above will also be relevant to the EBP Scenario, but the impact is

assumed to be much greater, with more households opting for the most efficient products

available, (e.g. a greater number of homes will attempt to achieve Code for Sustainable

Home level 6 thus requiring more water efficient showers)

Additional factors are assumed to result in particularly positive responses to these polices

and other activities under the EBP scenario.

Section 2.4 sets out the base year (2010) assumptions that underpin all three scenarios.

Section 2.5 expands on this describing how water efficiency would manifest under

alternative future scenarios.

Table 2.2 presents more detailed assumptions on how these policies would manifest under

each scenario. Table 2.3 presents the key assumptions of ownership, frequency of use, and

volume per use. Table 2.4 summarises how sales of different product types is projected to

change over time, under the three scenarios. These projections are illustrated in Figure 2.2,

and the impacts on projected stock levels are illustrated in Figure 2.3. The actions that would

be required for this to take place and for the projections to be realised are presented in

sections 2.5.1 to 2.5.3.

2.4 Base year and generic assumptions

The MTP model disaggregates showers into a several sub-products based on electrical

power rating, and variants of mixer shower (Appendix A)2. The results are presented in the

following categories:

Electric showers (all electric);

Gravity showers (mixer and bath/shower mixer); and

2 Further information regarding shower categories and classification is included in: BNWAT08: MTP

Modelling and Assumptions.

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Power showers (mixer with integral pump, mixer with separate pump and mixer

pressurised, including combination boiler mains fed systems).

The following assumptions have been applied to calculate all three shower projections:

Ongoing development of new-build homes3 has increased the market for bathroom

products in England and Wales. The demand for additional housing, in-line with

changing demographic factors including a higher proportion of single-person

households, will continue to stimulate the new-build sector.

An estimated five million new homes will be built by 2030. House builders choose to

install en-suite bathrooms in a wider variety and greater number of homes which

increases the overall number of showers.

Increasing numbers of existing homes are modified to include additional bathrooms

and/or en-suite facilities. This continues to drive an enlarged shower market.

In 2010, 81 per cent of households in England and Wales had at least one shower

installed: 39 per cent of households had a main shower that was electric; 42 per cent

had a main shower that was a mixer shower; 19 per cent did not have a shower.

There are 19.5 million showers in stock in homes in England and Wales.

In 2010, 1.9 million showers were sold.

By 2030, 2.6 million showers will be sold per annum.

Electric showers have a lifespan of 10 years (with an assumed standard deviation of

five years).

Mixer showers have a lifespan of 12 years (with an assumed standard deviation of five

years).

In 2010 the frequency of showering (excluding other forms of bathing) was 1.04 times

per person per day. This is expected to increase.

The main factors affecting the amount of water used when showering are the flow rate

and duration of shower:

The MTP model calculates volume per use by multiplying the flow rate by the

showering duration.

Shower duration is expected to increase. The model assumes duration of 5.31

minutes in 2010 increasing to 5.4 minutes in 2015 and 5.5 minutes from 2020

onwards.

The model calculates the weighted average flow rate for all mixer showers (gravity and

power). It then calculates consumption based on the weighted average of the product

ranges being sold and consumption in existing stock. This takes the impact of savings

through retrofit devices into account.

Further detail on the implications of population growth and housing development on the

shower market is presented in Appendix C.

3 England: www.communities.gov.uk/documents/housing/xls/table-104.xls

Wales: www.communities.gov.uk/documents/housing/xls/table-106.xls

http://www.communities.gov.uk/documents/housing/xls/table-104.xls

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Table 2.2 Shower scenario projections assumptions

Scenario Reference Policy EBP

Total ownership

Ownership of mixer showers is assumed to

increase from 42 per cent (of all households) in

2010 to 52 per cent in 2030 and electric showers

from 39 per cent in 2010 to 42 per cent in 2030.

The ownership of showers is the same as the

reference scenario, however the flow rates of

both electric and mixer showers are slightly less

than in the Reference Scenario.

The ownership of showers is the same as the

Reference Scenario; however the flow rates of both

electric and mixer showers are much less than in the

Reference Scenario.

New build installations

The Code for Sustainable Homes (CSH) and the

Building Regulations drive uptake of water efficient

shower heads, but this activity does not reverse the

overall trend of increasing shower water

consumption.

More new homes are built to higher water

efficiency standards adhering to the Building

Regulations or the Code for Sustainable Homes.

Consequently, the average flow rate of showers

declines as more water efficient shower heads

and/or flow restrictors are installed.

More new homes are built to the highest water

efficiency standards set out in the Code for

Sustainable Homes.

Replacement of existing stock

The market for shower products increases as more

people switch from bathing to showering. Electric

showers are particularly popular. Plumbing

systems in the UK are moving towards combination

boilers and mains hot water systems. Within the

mixer shower range, power showers are

increasingly common.

The difference between the Policy and EBP Scenario

is the more rapid slow down in sales of power

showers in existing homes.

Flow rate The average flow rate of electric showers increases

from 5 litres to 5.07 litres by 2030. Mixer shower

volumes decline from 9.4 to 9.1 litres by 2030.

Flow rates from electric and mixer showers

decline at a faster rate: from 5.0 and 9.4

litres/min in 2010 to 4.8 and 8.9 litres/min by

2030, respectively.

Flow rates from electric and mixer showers decrease

more significantly and at a faster rate, from 5.0 and

9.4 litres/min in 2010 to 4.1 and 6.9 litres/min by 2030.

respectively.

Frequency of use

There is an overall increase in showering as more

people switch from taking baths to showering.

Overall frequency of showering increases due to

the immediacy and convenience of showers

compared to baths.

The frequency of use increases further with the

policy and EBP scenarios. This is supported by

research undertaken by United Utilities that

indicates there is a growing trend toward daily or

twice daily showering because of the ease of

taking a shower4.

There is an overall increase in showering, with both

electric and gravity shower use increasing as

showering in general increases.

Frequency of use increases which reflects the shift

from bathing to showering as per the policy scenario.

4 United Utilities (2007). Water and energy efficient showers. Project Report

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Table 2.3 presents the ownership, volume per use, and frequency of use data used in the

MTP model, which may help to inform demand forecasts.

Table 2.3 Ownership, volume, and frequency of use

Reference Scenario

Year 2010 2015 2020 2025 2030

Ownership: Electric shower 0.39 0.44 0.46 0.47 0.48

Ownership: Mixer shower 0.42 0.45 0.46 0.45 0.46

Frequency of use 1.04 1.09 1.16 1.19 1.21

Volume: Electric shower 26.54 27.37 27.88 27.88 27.88

Volume: Mixer shower 49.80 49.99 50.58 50.21 50.03

Policy Scenario

Year 2010 2015 2020 2025 2030

Ownership As per the Reference Scenario

Frequency of use 1.04 1.12 1.21 1.27 1.33



EBP Scenario

Year 2010 2015 2020 2025 2030

Ownership As per the Reference Scenario

Frequency of use 1.04 1.12 1.21 1.27 1.33



See BNWAT08: Modelling and Assumptions for information on the assumptions

Mixer shower volume is a modelled average of the different types of mixer shower that are

available. The dramatic reduction in mixer shower volume under the EBP Scenario by 2015

reflects the change in the mix of shower type sales, particularly the reduction in sales of

showers with integral pumps which have a much higher flow rate than other types of mixer.

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Table 2.4 Product mix of showers under the scenarios

Percentage of sales: England and Wales – Reference Scenario

Sub Product Electric Mixer Power shower

Average flow rate (l/min) 5 7.2 11.8

2010 48 27 25

2015 50 26 24

2020 50 26 24

2025 51 26 23

2030 51 26 23

Percentage of sales: England and Wales – Policy Scenario



2010 48 27 25

2015 49 27 24

2020 50 28 22

2025 51 29 21

2030 51 29 20

Percentage of sales: England and Wales – EBP Scenario



2010 48 27 25

2015 49 27 24

2020 50 29 21

2025 51 30 19

2030 51 32 17

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Figure 2.2 Shower sales under the scenarios

Shower Sales Reference Scenario

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Figure 2.3 Shower stock levels under the scenarios

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2.5 Actions

Action is required to transform the market. Many of the actions require Government to take

the lead but other stakeholders would be required to take ownership of actions to ensure that

market transformation takes place.

2.5.1 Actions to achieve the Reference projection

The Reference Scenario is not very demanding. It requires current policies and activities to

continue, such as the manufacture, sale and promotion of efficient showers.

Actions to deliver the Reference Scenario projection:

Manufacturers should continue to produce the water efficient showers that are

currently available.

Water companies should continue to inform customers on water efficiency in general,

how they can save water in the shower, and how saving hot water will help them to

reduce their energy bills. This is a key action, required to address ongoing concerns

regarding the performance of efficient showers.

Retailers should to continue stocking water efficient showers, shower heads and flow

regulation devices.

The manufacturing and retail sector should consider whether testing regimes are

required in order to enable meaningful labelling schemes for shower performance to be

developed. Testing should reflect real-world conditions, taking account of how mains

supply pressures affect shower flow rates. Testing results should be shared and

should be used to influence design and manufacture, if appropriate.

2.5.2 Actions to achieve the Policy projection

The focus of the Policy Scenario is to encourage sales of „normal‟ mixer showers at the

expense of power showers. No action is required to further encourage uptake of electric

showers.

Participants at a “Guardian Sustainable Business”5 event discussed the approaches that

successful businesses are using to influence consumer sustainable behaviours and

procurement choices. One key point is that business and Government should move away

from trying overtly to convince people to change. Messaging and influencing actions need to

be much more subtle, appealing to relevant values and behaviours that will in turn generate

the procurement choice required. Appealing to peoples‟ values to change behaviour is one

option, but actively incentivising people to change their behaviour can in turn lead to a

change in values that may be sustained in the longer term. The following list of actions

5 http://www.guardian.co.uk/sustainable-business/events (quotes protected under the Chatham House

Rule).

http://www.guardian.co.uk/sustainable-business/events

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includes various steps to implement the policies that have been specified, but also actions

that target consumer procurement choices:

Purchasers of water-using products (i.e. the public) need to know who they can trust to

give them information on the consumption level and performance of products. At a

stakeholder workshop in 2010, the general consensus was that information is better

received from sources that are independent of the water companies. Stakeholders

across the industry need to work together to identify/develop a source of information

that is independent, credible, and trustworthy. This would support the next action:

The Water Industry (companies and regulators) should examine the feasibility of

targeted pressure regulation in homes in areas where high mains pressures are

unavoidable6.

To achieve the Policy Scenario, customers need to be actively dissuaded from

purchasing power showers. This would be achieved through a combination of better

information and financial measures. Water companies and energy companies should

give customers more information on how their water and energy consumption is

affected by high volume showering, supported by information on products that are

available to help them to reduce their shower flow rate.

Manufacturers and researchers should continue to work together to continue improving

the shower experience as well as the style of water efficient showers, so that there is a

water efficient showerhead to suit all bathroom styles. Shower manufacturers should

produce and promote water saving showerheads that limit flow without impairing

customer acceptance. They should be fixed-head and not provide the user with an

opportunity to select higher flow setting7.

The Bathroom Manufacturers Association (BMA) should pursue the implementation of

a single, consistent product labelling scheme to be adopted by manufacturers and

retailers within England and Wales. This would require leadership from the BMA to

encourage collaboration between manufacturers and retailers to progress this.

Product labels should provide clear information on how much water (including hot

water) the product uses, how this translates into the water efficiency level of the

product, and the energy and carbon implications of the shower (comparative to other

products that are available).

A labelling scheme once developed, should be applied to all UK sales (including

imports). Any scheme needs to consider the risk that some customers could be

deterred from buying a shower labelled as „efficient‟ or ranked with a low flow rate

because they assume that these products will be less effective with lower

performance.

6 United Utilities (2007). Water and Energy Efficient Showers. Project Report 7 United Utilities (2007). Water and Energy Efficient Showers. Project Report

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The Government, water companies, energy companies, and manufacturers should

make more use of the studies that have been done to examine the relationship

between shower flow rate and shower performance (as perceived by user). This

information should be more widely distributed to help combat perceptions that water

efficiency leads to an inadequate shower experience.

Marketing strategies for water efficient showers need to be developed so that the

emphasis is on the most modern, best available technologies, rather than reduced flow

rate. It is recommended that the BMA takes the lead on this, liaising with its members

on the importance of appropriate messages.

Public workshops have suggested that information on its own is insufficient to change

buying habits and that financial incentives are needed to persuade customers to buy

water efficient showers. The cost of products needs to be examined in detail to clarify

if there is a price premium on water efficient products. Further action would then be

necessary to target this. Fiscal incentives could be considered, however, this action

may be more appropriate to achieve the EBP Scenario.

Under a Policy Scenario it is unlikely that manufacturers will stop producing high flow

„luxury‟ showers. Retrofit devices that can be installed in new and existing showers

are more likely to be acceptable. The Government, water companies, and energy

companies should work together to influence retailers to include water efficient shower

heads and flow restrictors within their product range, and actively promote these to

customers, alongside the standard shower units, with the consumption information.

The market must be able to respond to changes in demand, so that customers can

access more water efficient products. Retailers need to provide a range of water

efficient products in different styles. These products need to be clearly promoted in

store and online.

The Policy Scenario assumes that sustainable water using products will be promoted

by organisations such as the BMA, and manufacturers/retailers keen to demonstrate

their green credentials.

2.5.3 Actions to achieve the Earliest Best Practice (EBP) projection

To achieve the flow reductions required under the EBP scenario the Government may

need to consider introducing specific maximum flow limits for shower installations.

However, this would not be possible through the Building Regulations which would

only reach new build homes. Amendments to the Water Supply (water fittings)

Regulations may be the most effective EBP route, but the Regulations must be

compatible with legislation regarding European trade barriers.

Fiscal incentives (or disincentives) to dissuade customers from buying inefficient

shower products should be considered. The retailers and manufacturers should

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consider development of a scheme to encourage the removal of existing power

showers or installation of low flow retrofits.

Some water companies (e.g. Portsmouth Water8) already have a policy to meter

customers who have a power shower (in the same way as they meter on ownership of

a sprinkler) but this is not universal and there is no information on how this is enforced.

Under an EBP scenario this is a policy that if implemented on a wide scale could

significantly influence people‟s decisions to buy and install a power shower, although it

is likely that this would meet with some resistance from customers and retailers.

Retailers should amend their product lines to improve the availability of efficient

showers in place of power showers. It would be beneficial for all retailers to co-operate

and reach agreement regarding their product ranges to ensure a level playing field so

one retailer isn‟t benefitting from stocking higher volume power showers. The

Government may need to develop voluntary agreements with the major retailers to

begin the process. The BMA may have a critical role in facilitating discussions

between retailers and manufacturers to ensure that the manufacturing base and

product orders are aligned.

Retailers would have to manage customer expectations regarding the perceived

advantages of power showers. To help retailers, it is recommended that retailers work

with other stakeholders to inform customers on wider water resources management

issues and overcome perceptions about efficient showers.

8 http://www.portsmouthwater.co.uk/customer_services/default.aspx?id=256

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3 Environmental Benefits of the MTP

3.1.1 Reduced water consumption

This section quantifies how much water could be saved per person and across England and

Wales as a result of achieving the Policy and EBP scenarios. It takes into account the

population forecasts published by the Office of National Statistics. The water saved is

assumed to be potable water. The calculations are based on the assumptions set out in

Section 2. Figure 3.1 illustrates the projections of total water consumption from showers

across England and Wales. Table 3.2 summarises the main results and quantifies the water

savings.

Figure 3.1 Total annual shower water consumption across England and Wales

Shower water consumption - England & Wales

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Table 3.2 Total annual shower water consumption across England and Wales

Total WC consumption (Ml/year) Total (Ml/yr) Saved

Year Reference Policy EBP Policy EBP

2000 220,711 220,711 220,711 0 0

2010 325,577 325,577 325,577 0 0

2015 352,531 357,023 345,643 4,492 6,888

2020 402,945 415,270 369,431 12,325 33,514

2030 478,059 512,972 405,081 34,913 72,978

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Water consumption is highest in the Policy Scenario due to increased numbers of people

showering more frequently as policies and social trends favour showering rather than

bathing. Figure 2.2 shows that overall shower and bath water consumption is lower in the

Policy and EBP scenarios than in the Reference Scenario.

These figures are based at the national level and whilst saving water is an issue for the

whole country, the „value‟ of water is likely to be greatest in areas of water stress, particularly

the south and east. More information on this is available in the Environment Agency

publication, Areas of Water Stress Final Report9. Demand management is a key option to

reduce pressure on resources. However, in many parts of the country demand for water is

driving the need for water transfers and other supply side options.

Significant energy is required to transfer water (raw water or potable) and to treat raw water

to potable quality, lower quality raw water requiring more treatment and thus more energy.

Therefore, the „value‟ of saving water is greatest in areas where pumped transfers of water

are greatest, and where there are significant treatment requirements.

3.1.2 Reduced energy consumption

This section is concerned with the potential energy savings that households could achieve

under the Policy and EBP scenarios. More detailed information and facts on the relationship

between water and energy use is available within BNWAT07 Water and Energy Use.

Embodied energy in Showering

By reducing the volume of water that is required for shower use it is possible to reduce the

amount of water that is abstracted, treated, distributed (clean water), and moved through the

sewer collection system to be treated (wastewater). Therefore, less energy will be required

within these services. However, it should be noted that the impact of reduced volumes will

have a negligible impact on the energy requirements associated with treating wastewater to

discharge as this is largely driven by load (quantity of contaminant matter rather than total

volume of water).

In England and Wales households use approximately 1.1 million Ml of hot water each year

(excluding washing machines and dishwashers) and this is forecast to increase to 1.3

million10 Ml/yr by 2030 unless hot water is used more efficiently11. Total carbon emissions

arising from hot water use in households is approximately 9.9 MtCO2e/year (1.5 per cent of

the total UK net carbon emissions12. Boiler inefficiencies are a key element driving high

energy consumption and associated emissions.

9 Environment Agency (2007). Areas of water stress: final classification

10 BNWAT08 Water and energy use.

11 2010 water sector MTP model

12 BNWAT08 Water and energy use.

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Energy directly associated with Showers

Showering requires hot water, which is heated in the home, usually by either a gas-fired

boiler or by the element in electric showers. Pumped showers use additional energy. The

2007 study by United Utilities13 reports that a pump uses 300 watts per use.

The amount of energy used by a shower depends on the following factors:

The type of water supply system (see Appendix D.4);

Boiler efficiency (electric showers are assumed to be 100per cent efficient);

Heat losses in internal plumbing systems;

Showering water temperature;

The power rating of the shower (for electric showers);

Type and presence of a pump (for certain types of mixer shower); and

Duration of shower.

Figure 4.3 shows the projected demands for household hot water use (showers) in England

and Wales under the Reference baseline, Policy, and EBP scenarios. Reducing water use

by transforming the market towards more efficient water using products will also reduce

energy use.

13

United Utilities (2007). Water and Energy Efficient Showers. Project Report

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Figure 4.3 Hot water consumption from showers in England and Wales

Shower hot water consumption - England & Wales

0

100,000

200,000

300,000

400,000

500,000

600,000

1999 2004 2009 2014 2019 2024 2029

Wat

er c

on

sum

pti

on

(M

l/ye

ar)


Figure 4.4 Shower (hot) water carbon emissions projected to 2030

Total hot water use CO2e tonnes/year - England & Wales

0

1,000,000

2,000,000

3,000,000

4,000,000

5,000,000

6,000,000

7,000,000

8,000,000

1999 2004 2009 2014 2019 2024 2029

Ton

nes

CO

2e

(To

nn

es/y

ear)

Reference Policy (P1) EBP

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Table 4.3 Total annual carbon emissions associated with shower hot water

Total Shower CO2e (Tonnes/year) CO2e saving (Tonnes /year)

Year Reference Policy EBP Policy EBP

2000 2,927,704 2,927,704 2,927,704 0 0

2010 4,157,553 4,157,553 4,157,553 0 0

2015 4,801,987 4,851,498 4,764,833 49,511 37,154

2020 5,519,084 5,663,900 5,206,279 144,816 312,806

2030 6,478,195 6,910,474 5,719,564 432,278 758,632

The results show that under the Policy Scenario carbon emissions would actually increase

within the shower group. This reflects the aims of the policies to increase uptake and use of

showers over baths. However, these results should be considered in line with the overall

results which clearly show that total carbon emissions in the Policy and EBP Scenarios

would be significantly lower than in the Reference Scenario, as the switch from bathing to

showering results in overall less hot water use for total personal washing.

More detailed information on water and energy is included in BNWAT07: Water and Energy

Use.

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4 Recommendations to progress the water sector MTP

The MTP needs to identify and implement actions to overcome customers‟ habitual

procurement decisions and reluctance to buy water efficient products:

In the longer term there is clearly a need for the MTP to take more and better account

of behaviour. Further work and decisions need to be made to confirm the appropriate

remit of MTP. Relevant areas may include: considering how existing behaviours and

perceptions affect consumer choice of products.

There is a clear need for more research to understand the drivers behind consumer

choice and then develop further actions directly targeting this important aspect of water

use. The MTP and the water industry need to understand more about public

perceptions of water efficiency. It will be important to consider how „efficient‟ products

should be promoted if user behaviour can easily render them inefficient. For example,

the promotion of low flow showers that do not provide an acceptable user experience

which are then removed.

Better and more effective use of international experience and case studies targeting

customer purchases would add value to the MTP. It is necessary to understand the

context of those situations, including the incentives that those overseas customers

have (EBP scenario). Reviews of international experience must consider factors

relevant to England and Wales specifically, including plumbing systems, drainage

systems, the price of water, and information on water scarcity.

When discussing water efficiency in new developments one issue that often come up

is the potential negative impact of reduced flows on drainage and sewerage

processes. The Environment Agency has published research examining the impact of

water efficiency on drainage14. Its report concludes that, while the full impact of

demand reductions on wastewater flows is not fully understood, it may result in

increased sewer blockages and other operational problems such as odour complaints

and sewer flooding…However, other issues such as the inappropriate use of sewers to

dispose of unwanted food and material based wipes, and the poor condition of some

drainage systems also contribute to the problem. It is important that water efficiency is

not excluded on this basis without all factors being taken into account and so the

Environment Agency results need to be more widely publicised.

Government, utility companies, researchers should continue to explore the potential to

deliver water efficiency in tandem with energy efficiency. The argument that saving

water, especially hot water, can help reduce household and industry energy bills is

powerful. However, whilst the unit price of water supplied is relatively low (e.g. 94p/m3

14

Environment Agency (2008) Less water to waste: Impact of reductions in water demand on wastewater collection and treatment systems. Science project SC060066, Environment Agency, Bristol.

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average England and Wales15) and the majority of households are still unmetered, the

financial incentive of saving „cold‟ water is not as strong.

In various situations stakeholders companies have expressed the opinion that whilst

water efficiency is appended to energy efficiency it will continue to be viewed as a

secondary, less important resource. Not all the reasons for saving water relate to

energy directly and until water is recognised as important in its own right many of these

issues will not be fully recognised. For example, low flows in groundwater fed rivers

and groundwater resources at risk of saline intrusion due to over abstraction.

Manufacturers have indicated that less desirable products would be phased out using

usual stock management methods. It would be useful for the MTP to better

understand these methods, and the usual timescales to phase out products. In the

longer term the MTP may seek more evidence on supplier capacity.

It is important to understand the size and influence of house-building at a national level

on product uptake. Also, the potential impact of Local Development Frameworks

influencing product uptake, is driven by the number of local authorities mandating, in

their Core Strategies that CSH targets are met.

The actions above target customers‟ propensity to change and their procurement decisions.

However, they need to be supported by actions to improve information classifying showers in

terms of their „resource‟ efficiency (water and energy) and performance:

Manufacturers and British Standards should to work together to develop test standards that

enable the performance of showers to be more readily compared (e.g. soap removal tests

and user experience). More information is required on the performance of showers under

different scenarios (including varying mains pressure), to enable the optimum balance

between performance and resource consumption to be estimated.

Actions to increase uptake of products that can be classified as water efficient require

clear definitions of water efficiency and product performance. At the moment there is

no clear definition of water efficient shower performance. A range of flow rates is used

to describe a product as efficient or highly consumptive. Using the methods in BS

6340 [Showers] manufacturers, the BMA and BSI should work together to improve the

definitions for future use.

Manufacturers should work together with academic researchers to develop a test

procedure to assess overall shower performance in terms of the additional comfort

parameters: temperature gradient and skin pressure. This should include a review

international shower test methodologies, notably those defined in the Australian and

New Zealand Standards and consider their applicability to the UK marketplace. Once

products can be assessed in this way, the results could be incorporated into labelling

15

Ofwat (online). Water service unit costs (2006-07). http://www.ofwat.gov.uk/legacy/aptrix/ofwat/publish.nsf/Content/rpt_int_08unitcostswater.html

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schemes to help consumers understand and compare the overall performance of the

products that are available.

The MTP should work with manufacturers the BMA and water companies to examine

and address the issue of multiple shower head units, to determine their impact on

consumption. Issues to be resolved include whether each shower head should be

rated individually and then averaged, or whether their ratings should be added

together. In the current review of the Australian and New Zealand Standard,

consideration is being given to defining the performance (including flow rate) of a multi-

head shower system as the sum of its parts. Some water companies, such as

Portsmouth Water16, have policies to compulsorily meter customers who have a power

shower. This type of policy should consider the overall flow impact of multi-shower

heads.

The industry needs to better understand the impact of water pressure on water

consumption and thus the efficiency of water using products, especially showers. The

Government and water companies should work together to organise data collation and

analysis of the main plumbing systems in England and Wales. It is recommended that

the MTP/water companies liaise with plumbing trade bodies to support this action. The

research should provide robust and easy to understand information on the impact

between water pressure and water consumption. It is possible that available water

pressure could be a limiting factor in the growth of very highly consumptive showers.

The outputs of this may impact on the development of a labelling system.

In line with stakeholder comments, longer term improvements of the water sector MTP may include:

Making more use of the MTP energy sector „What-if‟ tool for water using products. The

tool presents a range of scenarios on the future energy consumption until 2020 for

nearly 30 domestic and commercial products. As with the water sector MTP it includes

a Reference Scenario, a Policy Scenario, and an Earliest Best Practice Scenario. This

tool could provide an option to explore regional variation.

Implementing regular reality checks to ensure MTP is accurate and relevant.

Quantifying the uncertainty in the modelling outputs.

Collating better data to understand the base year situation and to inform the

projections. More work is needed to determine exactly what data would deliver the

required improvements: topic areas (e.g. household data, plumbing systems data,

behavioural research, product sales, etc), sources of data, frequency of updates,

quality assessment, responsibilities to provide and analyse data, etc. Any actions to

identify and collate data must take into account commercial sensitivities/confidentiality.

16

http://www.portsmouthwater.co.uk/customer_services/default.aspx?id=256

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It is important that the data relationship between the MTP and the data providers (e.g.

the water companies) does not become circular i.e. that water company data that is

based on the MTP briefing notes is not used as a source to update future MTP

information. Information on micro-components has been examined by isolating data

from the small number of companies that did not use the MTP to develop their own

analyses. The MTP should work more closely with the water industry to ensure that

the most appropriate and robust micro-component data continues to be made

available.

The MTP should work with Water UK, UK Water Industry Research (UKWIR), water

companies, and the Environment Agency to improve the quality of micro-component

use data and to re-affirm the baseline situation.

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Appendix A

Product details

A.1 Shower product definitions

This briefing note covers domestic showers only. It does not include safety showers, or

showers not intended for use by humans.

There are two main categories of shower: electric and mixer showers. The major difference

between the types is that electric showers heat the water in the unit so require only a cold

water feed, whilst mixer showers mix inputs from both hot and cold water feeds.

Table A.1 summarises the products included within the MTP models and the shower

volumes used to calculate consumption.

Table A.1 Shower product types included in MTP modelling

Product flow rate Factors affecting actual

volume Regulation/Approval

Electric shower

6 litres per minute* Duration, power capacity,

capacity to heat water to desired

temperature,

incoming water temperature

Building Regulation part 17K caps

total potential consumption. It

does not specifically target

showers.

Mixer shower (no pump)

5 to 15 litres/minute.

Average is

approximately 10-12

litres/minute

Duration, water pressure,

showerhead, flow regulation.

Water Supply (Water Fittings)

Regulations 1999 specify that any

person who proposes to install a

pump or booster drawing more

than 12 litres per minute,

connected directly or indirectly to

a supply pipe shall notify the

water undertaker to gain

consent**

Mixer shower with pump (powershower)

>12 litres/minute. Duration, water pressure,

showerhead, flow regulation.

* “A „good shower‟ by traditional UK standards” (Environment Agency 2007. Conserving water in buildings.)

6 litres/min is typical flow rate from electric showers stated by manufacturers during consultation.

** This requirement is primarily to prevent backflow but it does create an opportunity for water companies to

target pumped use where necessary.

Electric shower

An electric shower rapidly heats cold water as it flows towards the shower head, heating only

the water that is actually used. Electric showers have typical flow-rates of 3 to 8 l/min. The

flows are inherently low and any modification to the showerhead or flow characteristics could

damage the heating unit17. The power output of electric showers is measured in kilo watts

17

United Utilities (2007). Water and Energy Efficient Showers. Project Report.

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(kW) and varies between 7.5 kW to 10.5 kW. Higher rated showers are able to heat water

more rapidly and deliver higher volumes of heated water through the shower head. An

electric pump can be added to an electric shower to increase the flow rate if the water

pressure is low. A pumped electric shower is not the same as a power shower which is a

type of mixer shower.

Previous briefing notes have examined and projected consumption for each of the shower

power levels. The MTP has consulted manufacturers on this and has confirmed that this

does not add sufficient value in comparison to the level of complication that this introduces.

Therefore, electric showers are considered as one product. Duration of an electric shower is

not restricted to the volume of hot water that is stored in the system.

Mixer shower (sometimes referred to as a manual shower)

A mixer shower is one where the hose and spray come out of a wall unit and there is a

temperature control that blends the hot and cold water supply. Power showers are part of

this group. A gravity fed mixer shower typically runs off hot water from a tank/cylinder. It

can only feed hot water to the shower if the water has been pre heated in the hot water

cylinder. Once the tank is empty, there is no hot water until the boiler has refilled the tank.

Manufacturers suggest that mixer showers are best for homes with high-pressure systems.

Thermostatic mixer showers are essentially a manual mixer shower with an in-built

thermostatic mixing valve, suitable for installations in different types of property. The shower

unit is complete with a built in stabiliser to automatically adjust the water temperature, to

prevent scalding.

Mixer showers may incorporate a pump if the head in a gravity fed system is too low to

provide water at a preferred pressure. A shower pump is an additional piece of plumbing

equipment that is designed to push water through a gravity fed system where there is only

limited space (and thus limited water head) between the bottom of the cold water cylinder

and the shower location.

A conventional Power shower consists of a hot and cold feed (from stored supplies) and an

integral pump. The unit does not require an independent supply from the consumer unit as

no heating of water takes place. The integral electric pump increases the rate of flow from

the shower head, but can only be installed in a positive head of pressure position in the

property. Some manufacturers recommend these in homes with low water pressure as the

pump boosts the flow rate. However, this type of shower is the worst for saving water, and

can quickly use more water than a bath. It is also generally only installed in properties

where there is plenty of hot water storage, as pumped showers can deliver anything

between 11 to 25 litres of blended water per minute. This will drain the average sized

cylinder very quickly.

Shower panels are an all-encompassing shower panel, tower or column which incorporates

a fixed shower head and a shower handset in addition to body jets which combine to offer a

range of showering options. These units can be manually or thermostatically controlled.

The MTP has assumed these products are included as part of the power shower range.

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Bath shower mixer

This is the type of shower where the hose and spray are attached to the bath, often forming

part of the tap unit. The temperature and amount of water is adjusted by turning the taps.

Shower head

One of the main components within the shower unit that controls flow rate is the shower

head. There are products on the market that claim to limit the flow rate regardless of the

type of shower unit and water pressure within the property.

The shower head controls the flow and spray pattern of water. They come in a range of

shapes and sizes. A larger shower head with bigger holes uses more water per minute, but

isn't necessarily more powerful than a smaller one.

There are a number of shower head varieties specifically marketed as water saving, or water

and energy efficient. Aerating shower heads mix water with air, reducing the overall amount

of water that's needed. Other water-saving shower heads simply reduce the flow rate or

include a flow restrictor to the hose of the head to save water. Flow restrictors (or

regulators) are most appropriate as water efficiency retrofit products in homes where the

cold water tank is situated higher up in the house and the water pressure is higher.

It is important that a „water saving‟ shower head is suitable for the type of shower which it is

installed on. This is because the type of shower head installed will affect critical user

performance criteria, which if unsatisfactory are highly likely to result in the shower being

replaced with a more consumptive model. More detail on shower performance is in Appendix

D.3 but these critical performance criteria are:

Flow rate;

Area of coverage by the spray;

Force with which the spray acts on the user; and

Effectiveness in washing away soap.

Shower accessories

This briefing note is not concerned with shower accessories that do not directly influence the

consumption of the shower, e.g. type of shower valve, shower arms, riser rails, shower trays,

enclosures etc.

Shower body jets/multi directional showers/shower towers are additional water outlets which

spray water in addition to the shower head. These showers direct water in almost all

directions and so their use is limited to bathrooms large enough to allow the purpose built

shower enclosures required. They are thus are not suitable for placement in/over a bath.

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It is inadvisable to refer to specific shower types as „water efficient‟ or „not efficient‟ due to

the number of variables affecting how much water is used, and the context in which a

shower is to be used. For example, a shower providing less than 6 litres per minute may be

acceptable and more efficient than a 10 litre per minute model for a quick shower in an office

building, but in a house where demand and expectations are greater, 8 litres per minute may

be an „efficient‟ minimum. It is vital that the term „water efficient‟ does not become

synonymous with „poor performance‟.

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A.2 Volume per use

Volume per use is a function of the flow rate per minute and the duration of the shower.

Flow rate is relatively straightforward to measure, although the actual flow rate of a shower

unit can be affected by the water pressure in the system to which it is connected.

Mixer showers without pumps have typical flow-rates of 5 to 15 l/min. Mixer showers with

pumps have typical flow-rates from 10 to over 20 l/min. The fitting of a flow restrictor or

regulator, or change of showerhead can be used to reduce the flow of a mixer or pumped

shower18.

In 2009, Waterwise published a number of reports and press releases addressing the issue

of shower use, and duration of use. Of particular interest is a report19 arguing against the

claim that women spend much longer in the shower than the often reported average of

around five minutes, and that people over 55 are increasingly turning to showers, but

typically shower for a shorter time than other age groups20.

Information in the United Utilities 2007 study21 reports anecdotal evidence that the

interaction between personal washing products (e.g. showers) may interact with user

behaviour in such a way that produces unexpected results. For example, more efficient

showerheads may lead to an increase in the duration of showers, resulting in overall water

consumption. Behaviour and duration of use is highly variable and relatively poorly

understood.

A.3 Shower lifespan

Estimate of renewal rate

The lifespan of a shower is 15 years. As with other products this will vary from household to

household. Bathroom style trends may affect replacement rates. Plumbing and water

supply systems are likely to influence the consumers decision regarding replacing an electric

shower with a mixer shower or vice versa. Also, shower components may be replaced more

frequently due to damage and wear or tear (e.g. tarnished hose/shower head, broken

thermostat, broken electric dial). Components may be replaced like for like, unless the

whole bathroom suite is to be replaced. The MTP model assumes 15 years is the mean

average and around this is a normal distribution. More detail is available in BNWAT08

Modelling projections of water using products.

Stock data is not disaggregated into metered and unmetered households, i.e. there is

currently no data to show whether uptake of electric showers has been greatest in houses

18

United Utilities (2007). Water and Energy Efficient Showers. Project Report. 19

Waterwise (2009). Women are faster in the shower than we think. Press release, September 2009.

20 Waterwise (2009). Shower power press release. November 2009.

21 United Utilities (2007). Water and Energy Efficient Showers. Project Report.

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that are on a metered supply. There is no data on which to base estimates of stock

proportions in non-household properties. For more information on how product choice may

differ between building types, particularly between new and existing housing see BNWAT06

Water use in new and existing buildings.

A.4 Product innovation

Innovative products - Recycling showers

In these units water is used once in the showering process and is held in a storage tank and

recycled during a portion of the showering process in place of fresh water. One particular

product from Australia claims that, “the shower always starts with 100 per cent fresh mains

water and then cleans, filters and pasteurises the water before immediate re-use”. Many of

these products (e.g. Water Recycling Shower22 and the Quench Shower23 are still seeking

investment to come fully to market.

Current Manufacturing Capacity

The Bathroom Manufacturers Association (BMA) represents a large number of the

manufacturers trading bathroom water using fittings in the UK. The UK market is supplied

by manufacturers based within the UK and overseas. Within the UK the manufacturing base

is comprised of a mixture of companies with wide product ranges and a smaller number of

specialist companies manufacturing specialist „water efficient‟ products, for example

specialist showerhead companies. The relationships between manufacturers and retailers

vary with some manufacturers retailing their own goods as well as supplying retailers. Other

specialist water efficiency manufacturers provide products/parts to larger manufacturers.

Retailers source products from many suppliers.

Manufacturers and the BMA have stated that they have the capacity to respond to changes

in the market, shifting production to the more water efficient products quickly.

Non technical innovations

Other innovations that could help to transform the market include systems that would

actively encourage customers to opt for the most sustainable products. A labelling scheme

clarifying how much water the product uses based on an average water pressure to aid

comparison, could help consumers make more informed decisions.

There are also a range of products that aim to modify showering behaviour, such as shower

timers and bags for measuring shower volumes. Whilst user behaviour is particularly

important in driving water efficiency in showers, this aspect of water use is beyond the scope

of the MTP and therefore these products are not considered further in this briefing note.

22

http://www.recyclingshower.com.au/ 23

http://www.quenchshowers.com/

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Appendix B

The current market

B.1. Showering as a micro-component of water demand (England and Wales)

Water companies across England and Wales are forecasting water use from showering to

increase unless demand management measures are developed, implemented, and

successful24. All forms of bathing account for around 40 per cent of water use in households

(approximately 15 per cent in bath tubs, 10 to15 per cent by showers, and 10 per cent in

hand basins)25.

The Environment Agency collates and reviews micro-component data from the water

companies in England and Wales. Many of the water companies use the information in the

MTP briefing notes to develop their analyses. However, some companies develop their own

micro-component proportions without the MTP, using customer surveys and other

measurement systems. Figure B.1 shows that, according to these sources in 2010/11

showering accounts for 19 per cent of household demand for water. The figure is similar

when all the water companies‟ data are considered.

24

2009 Water Resource Management Plans 25

Water company micro-component data. WRc plc (2005) Increasing the value of domestic water use data for demand management – summary report suggests 10 per cent

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Figure B.1 Micro components of household water consumption

Source: Water company WRMPs (based on customer surveys)

B.2 Existing shower ownership

Shower stocks

There are approximately 19.5 million showers installed in homes across England and Wales.

Overall sales and subsequent stock levels of showers have increased significantly,

particularly since the late 1980s. Figure B.2 illustrates the historical trend. This increase is

due to a number of factors, including:

Growth in the new-build sector and demand for additional housing;

Increased number of single occupancy households;

Increased number of en-suite shower rooms;

Smaller homes/flats becoming more prevalent (which only have space for a shower

and not a bath);

Promotion of showers as saving water compared with baths; and

Lifestyle changes.

Showering 19per cent

2010

Toilet f lushing, 26%

Bath use, 14%

Show er use, 19%

Hand basin, 9%

Clothes w ashing,

10%

Dish w ashing, 7%

Garden use, 8%

Miscellaneous use,

6%

Car w ashing, 1%

Showering 19%

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Additional features add value to a property and many homeowners previously only having a

bath add a shower to provide more flexibility in bathing choice. Open walk-in showering

areas within the home, commonly known as wet-rooms, are also becoming very popular26.

Figure B.2 Historical trend in total shower stocks in England and Wales

Change in total shower stocks 1960 - 2010

0

5,000,000

10,000,000

15,000,000

20,000,000

25,000,000

1960

1962

1964

1966

1968

1970

1972

1974

1976

1978

1980

1982

1984

1986

1988

1990

1992

1994

1996

1998

2000

2002

2004

2006

2008

2010

Shower ownership is split fairly evenly between mixer showers and electric showers as

shown in Table B.1. The following data is based on updates to a detailed market research

investigation carried out for MTP in 2004. The updates are based on discussions with the

Bathroom Manufacturers Association and individual manufacturers. Future projections are

presented in Section 2.

Table B.1 2010 shower stocks in England and Wales – main products


47.9 per cent 27.2 per cent 25.0 per cent

Source: MTP shower model. Projections informed at the 2010 stakeholder workshop based on AMA research 2004

27.

26

http://www.armitage-shanks.co.uk/plan/faqs.html 27

AMA Research (2004). Micro component research into water conservation in domestic products

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Table B.2 2010 shower stock in England and Wales – disaggregated products

Electric showers kW Mixer showers Power mixer showers

7.0-7.9 8.0-8.9 9.0-9.9 10.0+ Gravity Mixer

Bath/ Shower Pressurised

Mixer with Integral Pump

Mixer - Separate Pump

0.61 3.07 3.45 2.19 4.34 0.95 1.9 1.86 1.07

3.1% 15.7% 17.8% 11.2% 22.3% 4.9% 9.9% 9.5% 5.5%

Units (millions)

Figure B.3 2010 Shower stock in households in England and Wales

Source: MTP Shower model

Shower sales

Another useful measure to understand the current market is sales data. This shows what

products are currently most popular. This is an important factor for the MTP which aims to

encourage uptake of the most sustainable products to transform the overall market and thus

water (and energy) consumption.

It is suggested that adding an additional bathroom28 and/or installing higher specification

bathroom products can add value to a property29. The trend towards high-quality products is

likely to stimulate the market, with an increasing proportion of consumers trading up to

higher specification products.

28

Nationwide (online). Housing Market Research. http://www.nationwide.co.uk/hpi/historical/What_Adds_Value_06.pdf 29

http://www.kingsbathroom.co.uk/news/bathrooms/2011/01/17/add-value-to-your-home-start-in-your-bathroom/

Detailed breakdown of product stocks 2010

Electric: 10.0+

kW, 11.2%Electric: 8.0-8.9

kW, 15.7%

Electric: 9.0-9.9

kW, 17.8%

Bath/Shower

Mixer, 4.9%

Electric: 7.0-7.9

kW, 3.1%Mixer -

Separate Pump

(power

shower), 5.5%

Mixer with

Integral Pump

(power

shower), 9.5%

Pressurised

mixer, 9.9%

Gravity mixer,

22.3%

2010 Stocks of the three main shower groups

Power

showers,

25.0%

Gravity

mixer

showers,

27.2%

Electric

showers,

47.9%

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Anecdotal information suggests that more home owners are replacing „unused‟ baths with

more stylish shower enclosures, particularly where space is limited. The trend towards more

powerful mixer showers continues supported by the increased range of shower accessories

the availability of larger enclosures designed for use with higher specification showers,

shower panels, body jets and wet rooms. However, there is also a trend towards more

powerful electric showers and features designed to improve installation. Better quality

showers may lead to a greater frequency of showering, particularly in the winter when

traditionally electric showers perform poorly. This would increase water (hot water)

consumption.

In 2010 approximately 1,980,000 showers were sold in England and Wales and the

proportion of sales per shower type is shown in table B.3. These data are based on stock

levels and replacement rates, updating the extensive research undertaken in 2004, and

through discussion with the BMA and individual manufacturers.

Table B.3 2010 proportion of sales market per product type

Electric showers kW Mixer showers Power mixer showers

7.0-7.9 8.0-8.9 9.0-9.9 10.0+ Gravity Mixer

Bath / Shower Pressurised

Integral Pump

Separate Pump

9,985 229,647 369,432 389,401 428,853 81,024 201,756 166,800 102,861

0.5% 11.6% 18.7% 19.7% 21.7% 4.1% 10.2% 8.4% 5.2%

Units (millions)

Figure B.4 2010 Shower sales in households in England and Wales

Source: MTP Shower model

Comparison of Figures B.3 and B.4 show that the proportion of sales for the main product

types closely mirrors the existing stock levels. However, within the sub-products there

2010 Sales of the three main shower groups

Power

showers,

24%

Mixer

showers,

26%

Electric

showers,

50%

Detailed breakdown of product stocks 2010

Mixer - Gravity,

21.7%

Mixer -

Pressurised,

10.2%

Mixer - Integral

Pump (power

shower), 8.4%

Mixer -

Separate

Pump (power

shower), 5.2%

Electric 7.0-

7.9 kW, 0.5%

Mixer - Bath /

Shower , 4.1%

Electric 10.0+

kW, 19.7%

Electric 9.0-

9.9 kW, 18.7%

Electric 8.0-

8.9 kW, 11.6%

Version: 1.0


appears to be a shift in electric showers towards the more powerful models that are available

such as the >10.0kW variant. This is clearly at the expense of the lower ranged power

showers. This suggests that the fundamental driving factors behind product choice are not

changing, but where there is an option that is perceived to offer better performance, i.e. a

more powerful electric shower, this significantly affects consumer choices.

It has been suggested that bath shower mixers are becoming less popular as wall mounted

(and thermostatic) mixers become more popular. The main reason for this is that the

temperature of mixer showers is more reliable as it is not affected by water being used

elsewhere in the home. These are all types of mixer shower.

B.3 Applicability of water efficient models per building type

In recent years there has been an increase in the number of studies commissioned by

Government departments and agencies to better understand water efficiency in different

types of buildings. The issue of water use patterns and product acceptability is considered

in more detail in BNWAT06 Water use in new and existing buildings.

The main difference for showers is that users may be more willing to accept reduced flow

fittings outside of the home, due to slightly different purposes and priorities. For example, a

shower installed in an office building will be used after a person has cycled to work etc. In

that situation the purpose of use will be entirely functional and the user is less likely to be

seeking a high power, luxury/invigorating shower as might be expected at home. Similarly,

users are less likely to require the more powerful and consumptive flow rates that are

preferred for shampooing and rinsing hair. Further, showers in non-household environments

(e.g. offices) may be used less regularly than a shower in the home and so users may be

more willing to accept low flow rates.

Table B.4 summarises the suitability of shower flow rates in households and non-

households. In many cases electric showers are the most efficient option, particularly in

non-household properties, where lower flow rates are more acceptable. This is in line with a

recent consultation issued by WRAP, Procurement requirements for water efficiency30.

Table B.4 Water efficient mixer showers in households and non-households

Water efficiency level

Households Non-households (offices etc)

Least efficient option >12 litres/minute >8 litres/minute

Baseline 12-15 litres/minute 8 litres/minute

Efficient 8-10 litres/minute 6 litres/minute

Highly efficient < 8 litres/minute <6 litres/minute

30

www.wrap.org.uk/downloads/2010_12_23_WRAP_water_eff_model_proc_reqs_v6_AG.3382370a.10378.pdf

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Appendix C

Transforming the market

C.1 Impact of globalised markets on England and Wales

As with other products increased awareness of the different product styles that are available

overseas influences consumer preferences and demand in England and Wales. Globalised

markets and global scale manufacturers directly influences the product ranges that are made

available in England and Wales.

More information from manufacturers and retailers dealing in the international market as well

as the England and Wales market would be useful to better understand how markets and

regulation elsewhere have directly affected their product ranges and how this has affected

the ranges they make available in England and Wales.

Overseas initiatives, such as the Water Efficiency Labelling and Standards (WELS) Scheme

in Australia, have influenced policy makers‟ views on the need for product labelling schemes

in the UK.

C.2 Factors that influence consumer use and uptake of showers

Uptake of any product is dependent on several factors including cost, user acceptability and

product performance. Detailed information on product performance testing and consumer

performance criteria are presented in Appendix D.3. However, there are specific factors that

have a significant impact on total shower stocks and the type of products that dominate

sales, as described for new/refurbished households and existing households below.

C.2.1 Housing development and refurbishment

The key driver behind growth in household demand for water is population growth. Figures

are currently rising, with the population of England and Wales forecast to rise from

approximately 55.2 million in 2010, to 63.0 million in 2030, an increase of 9.15 million31.

Housing data from CLG shows that the number of households in England and Wales has

increased from 17,025,000 in 1971 to 24,037,000 in 201032. Housing levels are forecast to

continue increasing in response to the increasing population and the increasing number of

low occupancy/single person housing. CLG data suggests that by 2030 the number of

households in England and Wales could reach 29,168,600.

31

http://www.statistics.gov.uk/pdfdir/pproj1009.pdf 32

England: www.communities.gov.uk/documents/housing/xls/table-104.xls Wales: www.communities.gov.uk/documents/housing/xls/table-106.xls

http://www.communities.gov.uk/documents/housing/xls/table-104.xls

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House builders are including en-suite bathrooms in a wider range of housing including flats.

In addition, the regeneration of urban areas and the overall shortage of available land have

increased the number of three-storey homes which often include a cloakroom, main

bathroom and en-suite.

Figure C.1 Housing and population forecast (England and Wales)

Forecast housing and population growth

20,000,000

21,000,000

22,000,000

23,000,000

24,000,000

25,000,000

26,000,000

27,000,000

28,000,000

29,000,000

30,000,000

2010

2011

2012

2013

2014

2015

2016

2017

2018

2019

2020

2021

2022

2023

2024

2025

2026

2027

2028

2029

2030

50,000,000

52,000,000

54,000,000

56,000,000

58,000,000

60,000,000

62,000,000

64,000,000

Households in England and Wales Population

Figure 4.2 shows that rates of house building, compared to annual stock levels, have

declined steadily since the1960s33. However, rates began to rise in 2002 and are expected

to continue to rise, despite the economic situation in 2010/11 as the Government steps up

measures to address the housing deficit.

33

Based on CLG historical housing data (interpolated up to 1990)

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Figure C.2 Historic and forecast rates of house building

Rate of housebuilding

0.00

0.20

0.40

0.60

0.80

1.00

1.20

1.40

1.60

1.80

1962

1966

1970

1974

1978

1982

1986

1990

1994

1998

2002

2006

2010

2014

2018

2022

2026

2030

New

bu

ild a

s %

of

exis

tin

g st

ock

*gaps exclude erroneous data Household occupancy in England and Wales has decreased from 2.84 in 1971, to 2.29 in

2010, and is expected to fall further to 2.14 in 203034. The same ONS data source also

trends changes in household size to 2008, as shown in Figure C.3.

Figure C.3 Historical trends of housing occupancy

Trends in household size

0

5

10

15

20

25

30

35

40

1971

1975

1981

1985

1991

1995

1996

1998

1998

2000

2001

2002

2003

2004

2005

2006

2007

2008

%

1 person 2 people 3 people 4 people 5 people >6 people

34

http://www.statistics.gov.uk/downloads/theme_compendia/GLF08/GeneraLifestyleSurvey2008.pdf

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The data shows that household occupancy appears to have levelled out following a period of

change between the 1970s and 1990s. The biggest change has been the rise of single

occupant housing which is now 30 per cent of the total housing stock at the national level.

C.2.2 Existing housing

While shower ownership is growing, there is still scope for further growth and there is growth

in multiple shower ownership.

The extensive exposure of shower products through DIY television programmes, lifestyle

magazines etc, has increased consumer awareness of the styles available in addition to

overall design co-ordination. Product development and the increasing range of styles and

technical features are likely to encourage a higher level of replacement and more frequent

replacement.

C.2.3 Product pricing

A key element that must be considered in the context of market transformation is product

pricing. If a product has a price premium associated with it then this is likely to negatively

impact on uptake. It is also important to recognise that whilst there may be no or very little

actual price premiums, the perception of price premiums may be sufficiently strong to

influence procurement decisions.

There is a large range in the price of showers available on the market. Research has shown

that price is affected by many variables, especially style and materials, and ease of

installation, rather than shower flow rate (water efficiency). Bulk purchasing can also drive

down costs. This briefing note deliberately does not specify prices because it will never be

able to accurately reflect the true range in the price of fittings at any one time.

Despite this, CLG has calculated the cost of building homes to meet the Code for

Sustainable Homes, in comparison to the cost of a „standard‟ build35. The information was

indicative but showed that the cost of installing appliances to meet level 3/4 for water is £125

more than to achieve level 1/2. The cost of the water efficient shower was included in this

total which also accounted for two low flush WCs and a smaller sized bath). However, there

is now anecdotal evidence that there no cost differential between „standard‟ and water

efficient versions.

C.2.4 User acceptability and product performance

Currently there is no single definition of „shower performance‟ and there is no standard way

of measuring it. The overall performance of a shower is the amalgam of several different

parameters, which in turn are influenced by the type of hot and cold water supply serving the

property:

35

CLG (2008) Cost Analysis of the Code for Sustainable Homes. Final Report.

Version: 1.0


Flow rate (real or apparent);

Area of coverage by the spray;

Force with which the spray acts on the user;

Effectiveness in washing away soap and shampoo;

Water temperature at the outflow

The water temperature differential between shower head and water at the foot/knee

level; and

Controllability.

There are currently no recognised test methods for „user performance criteria‟. However, a

study36 sponsored by United Utilities (UU) and undertaken by Liverpool John Moores

University (LJMU) in 2007 investigated showers in terms of both key physical performance

criteria and customer satisfaction. The report states that “WRc is using the results from the

study, on behalf of the Market Transformation Programme, to develop performance standard

tests for “spray pattern”, “spray force” and “soap removal” in order to more specifically define

water efficient showers”.

MTP identified the need to fully investigate all the factors influencing shower performance

and shower resource efficiency with the aim of devising a system of classifying, or defining,

showers such that:

- „Good‟ showers deliver a high standard of user experience, but with the least

resource consumption.

- „Poor‟ showers are those which either do not provide an adequate standard of

user experience or are unnecessarily wasteful of resources.

MTP does not cover the factors influencing consumer choice regarding the purchase of a

new shower such as style, size, cost etc. More detail on shower performance and testing is

available in Appendix D.3.

36

United Utilities (2007). Water and Energy Efficient Showers. Project Report

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Appendix D

Shower technical specifications and testing

D.1 Regulations

The Water Supply (Water Fittings) Regulations are national requirements for the design,

installation and maintenance of plumbing systems, water fittings and water-using appliances.

Their purpose is to prevent misuse, waste, contamination, undue consumption or erroneous

measurement of drinking water. These regulations do not regulate shower performance.

D.2 Standards

Definition: European Standard EN 13904:2003 defines a shower as a device for ablutionary

purposes which allows water to be emitted in the form of jets or water droplets.

The current European Standards for showers are defined on the basis of the water supply

system pressure. BS EN 13904:2003 (Low-resistance shower outlets for sanitary tapware)

is for showers which are to be used with low-pressure water supply systems.

BS EN 1112:1997 (Shower outlets for (PN 10) sanitary tapware) is the equivalent standard

for high-pressure water supply systems. Both of these standards include a methodology for

calculating the flow rate for showers.

BS EN 1112: 1997 for shower outlets includes a flow rate (hydraulic characteristics) test at a

dynamic pressure of 3 bar. The test is comprehensive and defines all the equipment

necessary to measure the flow rate at 3 bar without interpretation of the requirements by the

test engineer. BS EN 1112 is currently being revised and is undergoing public consultation.

This proposed revision includes measurement of the flow rate at both high and low pressure.

The revisions of the flow rate test in BS EN 1112 make it suitable for the measurement of

flow rate through all types of shower designs likely to be found in the UK market.

BS EN 13904: 2003 includes measurement of flow rates through low-pressure shower

heads. Whilst the test is well defined, it is not considered suitable for high-pressure shower

outlets and is likely to be superseded by the revision of BS EN 1112 when this is ratified by

the EU member states.

BS 6340: Part 4:1984 (Shower Units: Specification for shower heads and related

equipment). Whilst other parts of BS 6430 have now been fully or partially replaced, Part 4 of

BS 6340 is currently retained in the UK. The standard applies to the shower head or

handset only and defines tests to measure the flow rate, the spray form and the spray

trajectories.

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D.3 Shower performance criteria and tests

There have been numerous studies examining shower behaviour and consumer opinions. A

series of workshops were held by the MTP and reported in the previous briefing note

BNWATSH01: Consumer views about showers – summary report.

Flow rate through any design of shower can be measured using the test method in BS EN

111237. The primary components of this test are:

The water temperature should be less than or equal to 30 °C.

The water supply pressure should be 0.3 ± 0.02 MPa (for a high-pressure supply

system) or 0.1 ± 0.005 MPa (for a low-pressure supply system).

The flow rate should be measured once the flow has stabilised.

It is important to ensure that the water emanating from a shower head provides adequate

coverage of the shower user. This can be measured using the test method described in BS

6340: Part 438 with some minor modifications to the test method.

The primary components of this test are:

To comply with the standard, the shower head must achieve a minimum flow rate at

both 0.1 bar and at the lowest flow rate at which the „spray is well formed‟.

The spray form itself is then measured using an annular gauge and the trajectories of

the spray are also measured and must conform to the dimensions of an envelope

defined in the standard.

Test methods for flow rate and spray pattern are also specified in AS/NZS 366239, and BS

EN 1390440.

Force of spray. There are no published tests to measure the force of the spray emanating

from a shower head. Similarly, optimal pressure of the shower spray on skin is subjective.

There is a general tendency for people to prefer high rather than low spray pressure. Whilst

some showers have been found to be uncomfortably powerful41, there are often complaints

that over „aerated‟ showers have insufficient force.

37

BS EN 1112: 1997, Shower outlets for (PN 10) sanitary tapware, British Standards Institution, London.

38 BS 6340-4: 1984, Shower units. Specification for shower heads and related equipment. British Standards Institution, London.

39 AS/NZS 3662: 2005, Performance of showers for bathing. Standards Australia, www.saiglobal.com

40 BS EN 13904: 2003, Low resistance shower outlets for sanitary tapware British Standards Institution, London.

41 MTP (2006). BNWATSH01: Consumer views about showers – summary report

Version: 1.0


Temperature gradient (or thermal stability, or temperature uniformity) is another performance

criterion. This can be affected by droplet size although when questioned consumers barely

featured in their view of what makes a good shower. More important is the area of the body

that is covered by water, water covering a wide area is seen as preferable42. Focus groups

organised by Liverpool John Moores University in 200743 also found that customers want

showers to provide good water flow, at the right temperature, in order to wash and also enjoy

the experience of showering. It is perceived as important to have enough water running over

the body in order to keep warm in the shower.

Significant temperature differences between the water leaving the shower outlet and the

water falling on the shower tray can necessitate the use of additional hot water to achieve

the desired temperature and may also represent a danger associated with scalding. More

detail on this issue is covered in the United Utilities 2007 report, Water and energy efficient

showers – Project Report. The effectiveness of the water in rinsing soap could also relate to

temperature.

The 'WRc Approved' Scheme helps manufacturers demonstrate the performance of their

products. Quality, performance and installation issues are all covered in the assessment of

the product or service. 'WRc Approved' is an independent technical view on whether a

product is fit to do the job for which it is claimed or a contractor is fit to provide a specified

service. The 'WRc Approved' Scheme is owned and managed by WRc plc.

D.4 Impact of water supply systems on shower performance

The performance criteria are determined by a number of parameters including the:

Shower unit type.

Shower head type.

Type of water supply system and resulting water pressure and flow rate.

Length of dead leg of the pipe.

For mixer and power showers, the final temperature of the water delivered by the shower is

determined by a combination of the hot and cold water supply, which can vary in pressure

and flow rate depending on the type of system installed. The water pressure of the hot and

cold water feeds should be similar (i.e. both should be either high pressure or both low

pressure).

Mixing valves are used to obtain the desired temperature by adjusting the flow of hot and

cold water. Thermostatic mixing valves maintain a reasonably steady water temperature,

which can help to overcome the effects of variability in the hot and cold water supplies to the

shower unit.

42

MTP (2006). BNWATSH01: Consumer views about showers – summary report 43

United Utilities (2007). Water and energy efficient showers. Project report.

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Electric showers are connected only to the cold water system and so are unaffected by the

type of hot water supply in the property.

Cold water supply

The cold water supply affects all types of shower, both electric and mixers, and can be either

direct from the mains (high pressure) or fed by gravity from a tank (low pressure). With high

pressure cold water, any type of shower can be installed apart from a pumped shower.

With a low pressure system the shower must be selected to be able to perform at a low

pressure. Pumped, electric and normal gravity-fed mixers can be installed. The head of

water must be known prior to the installation in order to ensure that the correct pressure is

available for the shower unit.

If any of the shower performance criteria are not met then the shower can be considered not

to be fully serving its purpose. However this also provides the opportunity to change one or

more of the factors to reduce the water usage whilst providing the optimum shower

experience. For example, a reduction in the flow rate could be compensated by altering

another factor, such as the force of the spray that acts on the user and/or the area of

coverage by the spray.

Hot water supply

Hot water supply is important for mixer and pumped showers. Hot water supply, like cold

water, can be either mains fed (high pressure) or fed from a tank (low pressure). In addition,

the hot water supply can be either instantaneous or fed from a water storage cylinder. How

the hot water is supplied will affect the performance of a shower.

Version: 1.0


Figure D.1 Hot water supply systems in the UK

Combination boilers (mains fed) reduce the flow of the hot water within the boiler to allow it

to be heated. Flow rates are generally good when only one outlet is being used. However,

simultaneous draw-offs from different outlets will cause the flow to rapidly reduce. Hence it

is essential to use a shower that is equipped with a thermostatic mixing valve to maintain an

acceptable temperature and prevent scalding.

Where hot water is supplied from a storage cylinder, the cylinder must be large enough to

supply water to the shower as required otherwise the hot water feed runs cold and severely

impacts on shower performance.

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Related MTP information

BNWAT06: Water use in new and existing buildings

BNWAT07: Water and energy use

BNWAT08: Modelling projections of water using products

Briefing Note BNW09: Tumble drier test methodologies

Changes from earlier versions

This briefing note replaces the following previous briefing notes:

BNWATSH01: Consumer views about showers – summary report

BNWAT24: Performance and efficiency: reviewing and defining showers

BNDW Shower: Shower design and efficiency- briefing note relating to policy scenario objectives in Policy Brief

BNWAT25: Recycling showers – innovation briefing note and incorporates the previous briefing note:

BNWAT21: Performance standards for water using products – an overview

Consultation and further information

Stakeholders are encouraged to review this document and provide suggestions that may improve the quality of information provided. Email [email protected] quoting the document reference, or call the MTP enquiry line on +44 (0) 845 600 8951. For further information on related issues visit http://efficient-products.defra.gov.uk

http://www.mtprog.com/ApprovedBriefingNotes/PDF/MTP_BNW09_2007May1.pdf

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