Creating Low Energy Buildings, Energy at Home Event on Sustainable Buildings, Folly Farm Centre, 18th March 2015

creating low energy buildings

Colin Powell BA(Hons) DipArch Msc RIBA

gcp : architecture : energy : sustainable design

Content

• Energy – understanding the numbers

• Low energy design – step by step

• Going further – PassivHaus introduction

• Challenges for the designer

• Challenges for the builder

• Q & A


gcparchitecture : energy : sustainable design

Effective sustainable design

requires a detailed knowledge

of building science, technology

and construction

Our core skills as architects

provides our clients with a

depth of understanding that

informs our advice on energy

and sustainability

Our consulting business

provides the specialised

knowledge of sustainable and

low energy design needed to

help our clients achieve their

ambitions

i n t r o d u c t i o n


Being comfortable in our

home uses energy, for

heating, lighting, hot water

and appliances

To design low energy

homes the first thing we

need to understand is

where the energy all goes

to

Its all a matter of balance!

u n d e r s t a n d i n g e n e r g y i n b u i l d i n g s


The energy we use is

affected by different

factors

• Age of the building

E n e r g y i n b u i l d i n g s

62%19%

13%

3%3%

Home Energy

Heating

Hot Water

Appliances

Lighting

Cooking

Energy use – average all UK homes


The energy we use is

affected by different

factors

• Age of the building

• Lifestyle

• Purchasing decisions

E n e r g y i n b u i l d i n g s

32%

22%

29%

9% 8%Home Energy

Heating

Hot Water

Appliances

Lighting

Cooking

Energy use – new home to current regulations


Heat loss from the

building has to be

balanced with energy

(heat) in to maintain

comfort

We can calculate where

this heat is lost by

modelling

S o w h e r e d o e s a l l t h e e n e r g y g o ?


Heat loss from the

building has to be



comfort



modelling


walls

13.2

roof

9.2

floor

4.0

windows

24.2

ventilation

48.0

Current Regs - elemental energy loss – kWh / m2

Therm.

bridges

2.7


Heat loss from the

building has to be



comfort



modelling


walls

13.2

roof

9.2

floor

4.0

windows

24.2

ventilation

48.0


Therm.

bridges

2.7


s t e p s t o l o w e n e r g y d e s i g n

HANDOVER

ORIENTATION - SHADING - SHELTER - SUN

FORM - INTERNAL LAYOUT - SERVICES

INSULATION - AIRTIGHTNESS - THERMAL BRIDGES

THERMAL MASS

APPROPRIATE - EFFICIENT - SIMPLE

CONTROLLABLE


PERFORMANCE - INSTALLATION

OPERATION - UNDERSTANDING - CONTROL

COMMISIONING

RENEWABLES

SERVICES &

CONTROLS

BUILDING FABRIC

LAYOUT DESIGN

SITE


s t e p s t o l o w e n e r g y d e s i g n

SITE

LAYOUT DESIGN

BUILDING FABRIC

SERVICES &

CONTROLS

RENEWABLES

COMMISIONING

HANDOVER

ORIENTATION - SHADING - SHELTER - SUN

FORM - INTERNAL LAYOUT - SERVICES

INSULATION - AIRTIGHTNESS - THERMAL BRIDGES

THERMAL MASS


CONTROLLABLE


PERFORMANCE - INSTALLATION

OPERATION - UNDERSTANDING - CONTROL


H a c k n e s s F a r m – E a s t H u n t s p i l l

access access

mid-day

sun

• south-facing for passive solar gain

• Internal house layouts adapt to changing

entrance positions


• Internal layout: all main

rooms oriented to

south

• Ability to enter house

from north or south

• Larger windows to

south

• Smaller windows to

north

• Large south facing roof

for solar

• Simple (electric)

heating through fabric

efficiency


Traditional

construction

• Understood by

contractor, but tends

to greater complexity

• Challenges for

achieving airtightness

• Additional supervision

to maintain high

quality

• Importance of

controlling changes



Govt. Agenda for Carbon

Reduction – Climate

Change Act

35% Reduction in CO2 by

2020

Increasing energy costs

and prospect of increasing

energy instability

D o w e s t i l l n e e d t o w o r r y ?

DECC – monthly retail price indices

0

20

40

60

80

100

120

140

160

180

200

19

92

19

93

19

94

19

95

19

96

19

97

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98

19

99

20

00

20

01

20

02

20

03

20

04

20

05

20

06

20

07

20

08

20

09

20

10

20

11

20

12

Fuel price indices in the domestic sector in real terms 1992 to 2012

Coal andsmokeless fuels

Electricity

Gas


PassivHaus is a design

standard for producing

buildings with very low

energy demand

Developed in Germany in

1991, now being used

around the world as a tried

and tested standard

Market for PassivHaus in

Europe is huge. Market in

the UK is developing with

growing speed

C a n w e d o b e t t e r ?


Standard applicable to all building typesPassivHaus focusses on

building energy calculated

through a rigorous

calculation method

Not only applicable to

housing, it can be used for

large and small buildings

EnerPHit standard applies

PassivHaus principles to

refurbishment and retrofit

offices

schools

housing

student residence

q u i c k o u t l i n e


0

50

100

150

200

250

UK averagePart L 2010

PassivHaus

• Low carbon buildings are

not necessarily low energy

buildings!

• Focus on creating

buildings with energy use

significantly lower than

current normal practice

• Low Energy buildings =

Low Carbon buildings

- without the plug-in

technology fixes!

W h y P a s s i v H a u s ?

Specific heating demand – kWh / m2


Exeter City Council

Hastoe Housing Group

Interserve

University of East Anglia

Leicester City Council

Circle Housing

Gentoo

Diocese of Worcester

University of Bradford

London Borough of Tower Hamlets

Carmarthenshire Council

East Midlands Housing Association

Raynsway Properties

Estimated over 500 completed projects by end 2013 a rate of growth consistent with Germany 20 years ago(NHBC Foundation July 2012)

W h y P a s s i v H a u s ?

“healthy

buildings”

“addresses

fuel poverty”

“reduced

management &

maintenance”

“future

proof”

“not eco-

bling”“demonstrates

CSR”

“fabric first”

“massive cost

saving”

“tried &

tested”

“opportunity

for higher

revenue”

“right thing

to do”


• Exceptionally high thermal

insulation

• High performance triple

glazed windows

• Thermal-bridge-free

construction

• Very low air permeability –

airtight building envelope

• Comfort ventilation with

highly efficient heat

recovery

continuous thermal insulation

typically >300mm thick

larger windows to the south for

beneficial solar gains

continuous air barrier

To prevent air leakage

ventilation system delivers

fresh air to main activity

spaces

ventilation with

Heat recover to

save energy

F i v e p r i n c i p l e s


R e m i n d e r – w h e r e w e a r e n o w.

walls

13.2

roof

9.2

floor

4.0

windows

24.2

ventilation

48.0


Therm.

bridges

2.7


• There are over 37,000

completed PassivHaus

projects in Europe and

around the world

• There are approximately

46 completed PassivHaus

schemes in the UK

I t i s p o s s i b l e t o g o m u c h f u r t h e r !

walls

8.4

roof

5.2

floor

3.3

windows

13.7

ventilation

5.6

Therm.

bridges

0.0

PassivHaus - elemental energy loss – kWh / m2


• Increased cost for

construction is invested

in the building fabric and

insulation

• Typically 5-10% more

expensive

(recent studies show

this reducing)

• Payback period around

20 years

(but energy costs

increasing)

• Protection against

fluctuating fuel costs and

future uncertainty

C o s t s a n d b e n e f i t s

Illustration of energy cost savings for a 3-bed detached house


• Stable internal

temperatures without cold

surfaces or draughts

• Reduced risk of overheating

• Controlled ventilation can

reduce the risks of

respiratory disease

• Thermal performance and

air-tightness through

rigorous quality control at

design and construction

stage

Image courtesy of International PassivHaus Association

I t s n o t j u s t a b o u t m o n e y “We think each person lifted out of fuel poverty will save the health service about £250 a year. Data suggests there are 20% more deaths in Oldham in winter than in summer because of extra respiratory illnesses and heart problems [linked to cold homes]. If you get a cold winter and people cannot heat their homes, you get more people suffering and turning up in A&E”(Guardian Nov.13 – ‘Actively cutting energy bills in Oldham – Welcome to the Passivhauses’)


• What is important?

• Building form is a

crucial factor that

should be understood

as early as possible in

the design process

• Easier to achieve PH

standards with larger

buildings with more

efficient form factor

• Simpler building form is more efficient

• Relationship between building volume to surface

area will affect fabric insulation - and cost

t h e d e s i g n c h a l l e n g e


Goose Chase

• 200 sqm PassivHaus

• Site not ideal

• Overheating risk to

design out

• Simple form and

construction for ease of

build


Goose Chase

• ICF construction

• Fast and easy to build

• Highly insulated

• First air test 0.45 AC/H


• Simpler PassivHaus

buildings are more efficient

and easier to realise

• For designers early

understanding of the

necessary parameters is

vital

• Easier to build

• Easier to manage quality

• Easier to certify

• Reducing costs through

optimised solutions

Develop construction strategy at design stage


• Airtight construction

• Interior space enclosed in

a continuous barrier to

reduce uncontrolled

ventilation

• Materials and methods of

construction and jointing

• Position and protection

• Junctions and sealing

• Site control to achieve

continuity and avoid

damage

• Planning service installation to protect air barriers

t h e c o n s t r u c t i o n c h a l l e n g e


• Thermal bypass can reduce the effectiveness of

insulation by as much as 70%

Thermal bridge-free

• Thermal bridges are

created by fixings or

structural connections that

pass through insulation

• Thermal bridges can also

be formed by ‘thermal

bypass’ i.e. gaps in or

around the insulation

• PassivHaus aim is to have

zero thermal bridging

• Site control to ensure

careful installation and

sealing of insulation



Materials innovation

• Increased technical

requirements of

construction

• Prefabrication enables

quality control and ease

of construction

• Speedier construction

• Recycled content



• PassivHaus is a proven

standard based on

rigorous building physics

• Needs to be a target from

the outset

• All design decisions made

in the context of energy

implications

• For clients with on-going

responsibility for building

running costs PassivHaus

can offer ‘fixed’ energy

costs and early return on

investment

s u m m a r y

Fox Barn Hampshire – Jackson Planning

Student housing Dublin – Kavanagh Tuite Architects

Wimbish – Parsons + Whitley Architects

thank you


www.gcparch.co.uk

[email protected]

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Environment

Creating Low Energy Buildings, Energy at Home Event on Sustainable Buildings, Folly Farm Centre, 18th March 2015