Natural Resources�Canada

Ressources naturelles�Canada

PoolHeatingPoolHeatingSystems

Residential Solar

A Buyer’s Guide

Residential Solar Pool Heating Systems: A Buyer’s Guide

Prepared for Natural Resources Canada with the assistance of Taylor Munro Energy Systems Inc., Delta, British Columbia

This Guide builds upon the publication produced by the Ontario Ministry of Energy in 1982entitled Solar Heating for Swimming Pools, which is no longer available for distribution. This newGuide is distributed for informational purposes only and does not necessarily reflect the views ofthe Government of Canada or constitute an endorsement of any commercial product or person.Neither Canada nor its ministers, officers, employees or agents makes any warranty in respect ofthis Guide or assumes any liability arising out of this Guide.

Aussi disponible en français sous le titre : Chauffe-piscinessolaires résidentiels : Guide de l’acheteur

© Her Majesty the Queen in Right of Canada, 2001

Cat. No.: M92-223/2001EISBN 0-662-30665-1

About this Guide

This Guide has been preparedto assist consumers with thepurchase of a solar pool heaterfor their home pool. The Guideis not a “how to” manual oninstalling such a heater.

Natural Resources Canadabelieves that the numbers cited in this document – temperaturesand costs, for example – to beaccurate at time of publication.However, these numbers are pro-vided for illustrative purposesonly. Readers should expect somevariation between the numberscited in this document and those they find during their own research.

1

Table of Contents

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Why Should I Consider Solar Pool Heating? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3Five Good Reasons for Using Solar Heating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4How Does a Solar Heater Work? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5How Do Heat Pumps and Gas Heaters Compare to Solar? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6How Do Costs for Heat Pumps and Gas Heaters Compare? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7Summary – The Benefits of Solar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

How Can I Best Manage My Pool’s Energy Use? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9Pools Lose Heat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9Pools Gain Heat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10How Can I Reduce My Heating Load? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

How Does Solar Work with Different Pool Types? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14Outdoor Pools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14Indoor Pools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15Enclosed Pools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15Hot Tubs and Spas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

What Types of Solar Collectors are There? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16Unglazed Solar Collectors – The Common Collector for Solar Pool Heating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16Solar Collector Kit for Above-Ground Pools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18Glazed Solar Collectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

What Size Solar Heater Do I Need? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19Shading on the Pool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19Location of Solar Collectors – Orientation and Tilt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20Use of a Pool Cover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

How Will My Solar Heater Be Installed and Maintained? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21Most Collectors Can Be Mounted on Your Roof . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21Collectors Can Also be Mounted on Racks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22You Can Choose a Manual or Automatic Control Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23Activating the System is Straightforward . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23Maintenance is Easy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23Special Care Must Be Taken with Winterization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

How Do I Make the Best Decision as a Consumer? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24Selecting a Solar Contractor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24Selecting a Solar Collector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24Understanding the Collector’s Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24Determining Your Potential Costs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25Consumer Checklist . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Appendix 1: Other Applications for Solar Water Heating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27Related Publications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27Further Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Appendix 2: Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Reader Survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

2

There’s nothing like a refreshingdip to beat summer’s heat.Canada has about 600 000 back-yard swimming pools. Many owners use pool heaters to heattheir pools and in so doing endup spending millions of dollars ayear on non-renewable fuels.

As the cost of gas, propane, oiland electricity continue to rise,the cost of heating swimmingpools will become more and more expensive.

Fortunately, there is an economi-cal alternative that will cut yourenergy costs while you enjoy your swim – solar heating.

Solar heating is simple, reliableand has been used by pool own-ers for years. The initial cost ofsolar equipment is reasonable,and the operational savings are high.

The payback period – the time ittakes for your fuel savings to equalthe cost of your solar heating sys-tem – can be as short as two tothree swimming seasons. Afterthat, your energy savings continuefor the life of the system.

And, by replacing or reducing theuse of conventional pool heaters,solar heaters help to eliminategreenhouse gases, such as carbondioxide, that are having animpact on our climate.

Solar energy is a practical andeconomical way to heat yourpool, extend your swimming season and increase your swim-ming comfort.

Introduction

Tsawwassen, British Columbia.This 5-m x 10-m (16-ft. x 32-ft.) in-ground pool has six 4.4-m2 (4-ft. x 12-ft.) solar collectors.Photo courtesy Taylor Munro Energy Systems.

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3

A solar heating system for yourpool is an economical alternativeto expensive conventionalheaters. Solar collectors capturefree energy from the sun and useit to heat your pool.

They extend your swimming sea-son and reduce monthly fuel billswithout depleting non-renewablefossil fuels.

In fact, solar pool heating for yourhome is the most economical solarapplication in Canada today. Solarheaters already make up morethan 10 percent of all new poolheating-equipment sales.

Why should I consider solar pool heating?

Niagara Falls, Ontario.This 5.5-m x 11-m (18-ft. x 36-ft.) in-ground poolhas five 4.4-m2 (4-ft. x 12-ft.) solar collectors. Photo courtesy of Daystar Energy.

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4

Five good reasonsfor using solarheating From Victoria, British Columbia,to St. John’s, Newfoundland,Canadians are using solar energyto heat their pools. Here are fivegood reasons why.

No. 1: Solar saves on poolheating costsEnergy costs continue to rise. Inthe last two years alone, the priceof natural gas has more than dou-bled. On the other hand, the sun’senergy is free, and more and morepool owners are taking advantageof this opportunity to save moneyand avoid future price increases.

Over a 15-year period, you couldspend five times or more on heat-ing with gas what you wouldspend on installing a solar heatertoday. Once your solar heating system is installed, there are nomore heating bills to pay.

Many pool owners switch to solar because it meets all of theirheating needs. But, even if youcontinue to use a gas or electricheater as a backup, solar heating is a smart investment that willsave you money, year after year.

No. 2: Solar extends yourswimming seasonA properly sized solar heating sys-tem will get you swimming earlierin the spring and later into thefall. Whether or not you have anexisting heater, you can keep yourpool warmer and open longer withfree energy from the sun. In most

areas of Canada, a solar heaterused in combination with a solarpool cover can add two to fourweeks to the beginning and two to four weeks to the end of theswimming season.

No. 3: Solar equipment isdurableSolar equipment often lasts longerthan gas or electric heaters. Withproper yearly maintenance, youcan expect fuel heaters to lastseven to 10 years. Most gas heaterscome with a two-year warranty,and well-made heat pumps carry atwo-year warranty with five yearson the compressors.

Solar panels have a minimum 10-year warranty and generally last 15 to 20 years or longer.

No. 4: Solar requires lessmaintenance Unlike gas and electric heaters,which should be serviced by atechnician every year, a solarheater requires very little servicing.Again, that means less cost andless hassle for the pool owner.

No. 5: Solar energy isgood for the environmentThese days we hear a lot about thedamaging effect that burning fossilfuels is having on the environ-ment. Burning fuels releases nitrogen oxides that cause the formation of smog in urban areas.Urban smog, which is worse onwarm and sunny days, affects people with respiratory problemssuch as asthma. Using solar energyinstead of burning fossil fuels canhelp reduce this smog.

Burning fuels also produces carbondioxide, the main cause of climatechange. Replacing a natural gas orpropane heater with a solar heatercould stop three to 10 tonnes ofcarbon dioxide from entering theatmosphere each swimming sea-son. That’s about the sameamount produced by operatingyour car for one year!

5

How does a solarheater work?A solar pool heater is simple tooperate and doesn’t change theway you operate standard poolequipment. Figure 1 shows thecomponents of a typical solarheater. Solar collectors are usuallymounted on the roof of yourhome or other structure such as a shed or garage. This is the leastexpensive option and doesn’t takeup extra space on the property.When suitable roof space is notavailable, collectors can beground-mounted on a rack.

The existing pool pump is used to circulate water from the poolthrough the solar collectors andback to the pool. On sunny days,an automatic controller divertsthe water to the roof by a motor-ized valve. The automatic valveuses special temperature sensorsto determine when the solar col-lectors should be used.

For those on a budget, a manualvalve can be used. However, thistends to be an impractical optionfor most people because the valvemust be turned at least twice aday at exactly the right time.Automatic and manual valves and controllers are discussed inthe section on installing andmaintaining a solar water heateron page 21.

Figure 1. Components of a solar pool heater.

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vacuum breaker

solar collectors

reverse return

controller

filter

collector supply line

checkvalve

pumpintake

warmoutlet

pump

6

How do heatpumps and gasheaters compareto solar?Across Canada, some 60 percent of in-ground pools are heated.Although several different types of heaters are available, the mostcommonly used are natural gasheaters and electric air-source heatpumps. Natural gas heaters arepopular in British Columbia andOntario. In Quebec, where theavailability of natural gas is lesswidespread, heat pumps are morepopular. Roughly 10 percent ofheated pools already use solarheaters.

Since a heat pump puts out con-siderably less power than a naturalgas heater, it is important to cor-rectly size the heat pump to ensureadequate heating for your pool. Its low output also means that ittends to run continuously, whichcan be excessively noisy for somepool owners. And, while it offersthe advantage of being cheaper tooperate than a gas heater, a heatpump may be less reliable andmore prone to breaking.

A heat pump takes longer to raisethe temperature of your pool thana natural gas heater, which canraise a cold pool to the desiredtemperature relatively quickly.

During sunny conditions, a solarpool heater can add heat as well asor better than many heat pumps.The temperature of a solar heatedpool will fluctuate as weather con-ditions change. But, if a pool coveris used, the heat collected by solarpanels on a sunny day can easilyget you through a cool, cloudyperiod. And, water temperatureswill be back up again after anotherday or two of sunshine.

Because of our climate, manyCanadian consumers are scepticalthat there is enough sunlight tosupport a solar pool heater. In fact,there is more than enough solarenergy for pool owners acrossCanada to heat their pools with-out a backup heater from Maythrough September.

Figure 2 shows what daytime temperatures a solar heater canprovide for an in-ground pool inOntario during the swimming season. A solar heater in Ontariowill have no difficulty keeping a pool well above the desired temperature.

Solar pool heating can typicallyextend the length of your outdoorswimming season by two to fourweeks at either end. With a solarsystem, it costs nothing in fuel to try for an early start or a latefinish, whereas most people with a fuel heater can’t afford to opentheir pool until good weather is guaranteed.

Because a sufficient area of solarpanels must be used to obtainmaximum performance at mini-mum cost, accurate sizing of thecollector area is critical. See the section on determining collectorsize on page 19.

35.0�

32.5�

30.0�

27.5�

25.0�

22.5�

20.0

20-May�1999

09-June�1999

29-June�1999

19-July�1999�Date

08-Aug�1999

29-Aug�1999

17-Sept�1999

27.5 °C minimum�desired temperature

Daytime Pool Temperature

Tem

pera

ture

(°C

)

Figure 2. Typical temperature profile for a solar heated poolin Ontario.

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7

How do costs for heat pumpsand gas heaterscompare?Installation costsA solar heater is generally moreexpensive to install than a gasheater and less expensive than a heat pump.

Table 1 shows that in 2000 the typical cost of installing a solar pool heater for a 5-m by10-m (16-ft. by 32-ft.) pool, on asuitably located roof, would bebetween $3,100 and $5,000.

A professionally installed systemusually comes with a one-yearwarranty on the installation and a 10- to 12-year warranty on the collector. Ask your installerwhat the warranties come withyour system.

Operating costsOnce a solar heater is installedand paid for, the energy to heatyour pool is free. Solar heatingsystems are very easy for thehomeowner to maintain – theonly expense is your time. If youwant to hire a solar technician toperform annual maintenance, itwould cost approximately $100per year.

Using a natural gas heater, a typi-cal 5-m by 10-m (16-ft. by 32-ft.)outdoor pool would cost between$300 and $600 to heat from Mayto September, if you use a solarcover (see Table 2).

If no cover is used, the typicalcost is between $600 and $1,100.These costs are based on a naturalgas price of $9.13 per gigajoule,(GJ), so the fuel cost for your poolwill depend on your current costof natural gas. In addition, a rec-ommended annual cleaning of agas heater costs $50 to $100.

Depending on the price of electricity, a typical heat pump(with a summer coefficient of performance of 4.25) costs aboutone quarter to one half that ofnatural gas to operate.

Table 1. Estimated pool-heater installation costs for a 5-m x 10-m (16-ft. x 32-ft.) pool (figures for year 2000).

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Table 2. Typical pool-heater operating costs for a 5-m x 10-m (16-ft. x 32-ft.) pool (figures for year 2000).

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AdditionalType of Heater Heater Cost Materials Total Cost

and Labour Cost

Natural Gas $1,700–$2,900 $600–$2,000 $2,300–$4,900

Heat Pump $2,900–$5,900 $200–$500 $3,100–$6,400

Solar $2,500–$3,200 $600–$1,800 $3,100–$5,000

Type of Heater Fuel Cost Maintenance Total Cost

Natural Gas $300–$1,100 $50–$100 $350–$1,200

Heat Pump $110–$400 $50–$100 $160–$500

Solar $0 $0–$50 $0–$50

8

Summary – Thebenefits of solarThese graphs summarize fivegood reasons for using solarenergy to heat your pool.

No. 1 Solar saves on pool heating costs

Solar

Heatpump

Gas

No. 2 Solar extends your swimming season

Solar

Gasheated

Unheated

Free energyfrom the sun

Less than half the cost of gas

Highest energy cost

Adds upto twomonthsto seasonfor free

For use in goodweather; extendsswimming seasonat extra expense

Use pool only duringhottest months

No. 3 Solar is durable

Solar

Heatpump

Gas

Many lastyears pastwarranty

Shortest life due tomechanical wear and tear

Moderate, depending on usage

No. 4 Solar requires less maintenance

Solar

Heatpump

Gas

Minimal annual maintenance required

Complicatedmechanicalequipment

Moderatecorrosive wear

No. 5 Solar energy is good for the environment

Solar

Heatpump

Gas

Burns no fossil fuel

Burns less fuel than gas,depending on electricity supply

Releases as much carbondioxide as your car inone year.

9

Total Losses 38.3 GJ

Convective�17%

Evaporative�51%

Swimming�Pool

Radiative�27%

Make-Up�2%

Conductive�4%

Total Losses 26.9 GJ

Convective�24% Evaporative�

33%

Swimming�Pool

Radiative�36%

Make-Up�1%

Conductive�6%

How can I best manage my pool’s energy use?

Figure 3: Sample heat loss for an in-ground pool in Toronto, Ontario, in July with low cover use (left) and high cover use (right).

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Pools lose heat Since pools lose a large amount of energy, it is important tounderstand the different waysthese losses occur. Heat loss fromoutdoor swimming pools occursmainly from the surface in theform of evaporation, radiationand convection. Indoor pools loseheat primarily by evaporation.When in use, pool covers virtually eliminate losses fromevaporation and also reduce lossesfrom radiation and convection.

EvaporationTypically, evaporation accountsfor 30 to 50 percent of all heatlost from a swimming pool. In midsummer, most average-sized pools lose about 50 mm (2 inches) of water per week by evaporation, the equivalent of 150 kilowatt-hours or 500 000 BTU. These losses arehigher in dry or windy weather.Evaporation also removes sub-stantial amounts of expensivepool chemicals. Using a solarcover frequently will significantlydecrease these evaporative losses,as demonstrated in Figure 3.

Radiation Radiation transfers heat throughair from warmer objects to coolerobjects.

Radiation typically accounts for25 to 35 percent of pool heat loss.Most radiative heat loss occurs onclear nights.

Convection

Convection is the transfer of heatfrom the pool to the air by fluidflow. When the pump is not oper-ating, mixing warm and coolwater, the warm water rises to thetop of the pool. Then, throughconvection, the heat of the warmwater escapes to the cooler air. Ifthe wind is blowing, convectiveheat loss increases. As indicatedin Figure 3, convection typicallyaccounts for about 15 to 25 per-cent of total heat loss.

ConductionConduction is heat transfer byphysical contact through materi-als. A swimming pool loses heatby conduction through the pool’swalls and bottom. A high watertable or flowing ground water willcarry away an in-ground pool’sheat through conduction.

10

Pools gain heat Pools gain heat from whicheverheating system you choose toinstall. Any swimming pool in asunny location is also naturallyheated by solar energy. Sunlight is absorbed by the water, addingheat to the pool. This “passive”solar energy is a valuable com-modity to a pool owner to supple-ment an electric or gas heater. Anunshaded swimming pool costssignificantly less to heat than onethat is shaded.

Solar pool covers permit some ofthis passive solar heating whilealso reducing heat losses. Manyoutdoor pools require no auxil-iary heating during the peak ofthe summer (in July and August)when heat losses are low and sunshine is abundant.

How can I reducemy heating load?To reduce your heating load, you must use energy efficiently.Energy use can be affected bypool temperature, wind exposure,pool dimensions, pump operationand pool covers.

Figure 4 illustrates typical heatingcosts for an average in-groundpool that is heated by natural gas.

Monitor pooltemperatureThe energy consumption of anoutdoor pool depends on thewater temperature. For typicalpool activity, temperatures canrange from 26°C to 30°C. A poolheated to 30°C consumes almosttwice as much energy as a pool at26°C (see Figure 4). Allowing thepool temperature to drop whennot in use will save energy andreduce operating costs.

Decrease wind exposureThe evaporative heat loss in aswimming pool is greater as windvelocity over the pool surface isincreased. Generally, exposure towind can be divided into threeranges:

• sheltered – the pool is locatedwithin a high fence;

• moderate – the pool is locatedclose to a house or in a fencedyard; and

• open – the pool is not pro-tected from winds.

The costs shown in Figure 4 arebased on moderate wind expo-sure. Pools with an open exposureconsume approximately 50 per-cent more energy. Constructing a solid fence around the pool creates a sheltered exposure,reducing energy consumption by approximately 20 percent.

Figure 4. Natural gas heating costs for an outdoor swimming poollocated in Toronto, Ontario.

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2500 -

2000 -

1500 -

1000 -

500 -

0 -

Heating costs

Hea

tin

g co

st (

$)

26°C 30°C 26°C 30°C 26°C 30°CJune–July June–Aug May–Sept

Heating season (months)

■ Additional cost without a cover■ Cost with cover on 16 hours/day

• Typical heating costs for two pool temperatures (26°C and 30°C) for anin-ground pool, 5 m wide by 10 m long, with an average depth of 1.8 m.This is one of the most common pool sizes and is generally referred to as a 16-ft. x 32-ft., 6-ft.-deep pool.

• The costs are based on using a natural gas burner of 68 percent efficiencyand a natural gas rate of $9.13/GJ.

11

Optimize pool dimensionsIf you are a prospective, ratherthan existing, pool owner,remember that the size of poolyou choose will significantlyaffect its energy use. Since mostof a pool’s heat loss occurs fromthe surface, the energy use of different-sized pools can be estimated by comparing surfaceareas. For example, a 6-m by 12-m (20-ft. by 40-ft.) poolrequires approximately 55 percentmore energy than the samplepool in Figure 4 as its surface is 55 percent larger.

Reduce pool pump costsThe cost of energy to heat yourpool represents only a portion ofyour pool’s operating costs. Youmust also factor in the cost ofelectricity to run your pool pump.Most pools are equipped with a pump of at least 750 watts(approximately 1 horsepower)running 24 hours a day, circulat-ing water through a filter unitand a pool heater.

Based on this pump size, the elec-trical cost for operating 24 hoursa day is about $48 per month.You can use a timer on your pool

pump to reduce its hours of operation. An operating cycle of12 hours a day is recommendedand results in a saving of $24 a month.

Use a swimming poolcoverUsing a pool cover will save youenergy and maintain your pool’stemperature when it is not in use.If used frequently, a cover canreduce your pool’s energy con-sumption by up to 50 percent.

Using a floating plastic swimmingpool cover can significantlydecrease the amount of energyrequired for pool heating as wellas significantly reduce the loss ofwater due to evaporation.

Two cover types are available. Thefirst is a solar blanket (see Figure 5),which consists of a translucent cellor bubble arrangement of 0.3 mm(12 mil) polyethylene. It allowssolar radiation to warm the water.This cover primarily preventsevaporative heat loss but alsoreduces heat loss through con-vection and conduction. With careful handling to prevent bubble breakage, it can last two to three swimming seasons.

The second type, a thermal blan-ket (see Figure 6), consists of a 3 mm (1/8 inch) layer of closed-cell polyethylene foam covered by a protective layer of woven polyethylene.

It provides more insulation than a solar blanket, but because it isopaque it prevents solar radiationfrom warming the water. Leavingthe pool uncovered on hot dayswill help warm the water. If youhave a heated pool in a shadedarea, an opaque blanket is themost cost-efficient cover you can get. It can last from four tofive years.

SAFETY CAUTIONFor safety reasons, a cover mustbe completely removed from thepool before anyone goes swim-ming to make sure no one can be trapped beneath it.

Figure 5. Solar blanket.

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Figure 6. Thermal blanket.

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12

The effectiveness of any coverdepends on the amount of time itis on the pool. The more you useyour cover, the more energy youwill save. For example, a coverused 14 hours a day can save energy consumption by 50 percentor more.

COVERS FOR INDOORPOOLSPool covers are also suitable forindoor pools. Indoor pools losemost of their heat by evaporation,and a well-fitting pool cover canvirtually eliminate evaporativeheat loss. As excess humiditycaused by evaporation must beremoved either by ventilation orrefrigeration, a pool cover canhave the additional benefit of saving on the cost of humiditycontrol.

HANDLING POOL COVERSMost people don’t use their poolcovers as often as they shouldbecause they are bothersome andawkward. But, the more oftenthey are used, the more effectivethey are. Once removed, coversshould be carried to a storagelocation some place out of thesun. Covers for non-rectangularpools may be cut into several sections for easier handling.

The best and easiest way to storea pool cover is on a roller at oneend of the pool. Not only dorollers prevent damage to coversthat can be caused by constanthandling, they can usually beoperated by one person.

POOL COVER AND POOLMAINTENANCEPool covers and pools need maintenance. All covers requirean annual cleaning with mildsoap and water. In the winter,summer covers should be storeddry, rolled or folded and keptfrom freezing so that the plastic doesn’t crack. Consult the manu-facturer of your pool cover formaintenance recommendations.

No matter how you heat yourpool, the more efficiently yourheater works, the lower your fuelbills will be. Fuel heaters shouldbe cleaned and adjusted annuallyby a technician. Clean or back-wash sand filters regularly toreduce the work your pump must do.

Fonthill, Ontario.This 6.1-m x 12.2-m (20-ft. x 40-ft.) pool has a solar cover and eight 4.4-m2

(4-ft. x 12-ft.) solar collectors.Photo courtesy of Daystar Energy.

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13

Summary Here are some energy-saving tips:

• Allow the pool temperature to drop when it is not in use.

• Put a fence around your poolthat can act as a windbreak.

• Prospective pool buyers – thesize of your pool is a majorfactor in the heat energyrequired to keep it warm. Thelarger your pool, the largerthe surface area from which it loses heat. Your pool’s con-struction and location are also important.

• Maintain fuel heaters for optimum efficiency.

• When your pool is not in use,cover it to reduce evaporationand heat loss. Pool covers can save up to 50 percent of energy consumption.

• During sunny summer days,leave your solar cover on tominimize heat loss.

• If you use an opaque cover,remove it to take advantage of solar gain.

This solar heating system was installed in 1998 on a 5-m x 10-m (16-ft. x32-ft.) in-ground pool with six 4.4-m2 (4-ft. x 12-ft.) west-facing collectors, a solar blanket and a propane back-up heater. The owner comments, “I onlyreally wanted 83°F [28°C] but I could sure get more than that. It went up to94°F [34°C] before I turned it down! It doubled our season!”Pool owner: R. Desparois, Repentigny, Quebec.Photo courtesy of Heliocol Canada.

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14

Swimming pools come in varioussizes, shapes and types of con-struction. All types of pools canbenefit from solar heating.

The size of your pool is a majorfactor in the heat energy requiredto keep it warm. The larger yourpool, the larger the surface areafrom which it loses heat. Yourpool’s construction and locationare also important.

Outdoor poolsAbove-groundAbove-ground pools are usuallymade using prefabricated rigidfree-standing walls with vinyl liners. They are installed on theground after the surface has beensuitably levelled.

Because they are typically smallerthan in-ground pools, above-ground pools may be able toexperience a significant heat gain from a modestly sized solar heater.

In-groundIn-ground pools, either concreteor vinyl-lined, tend to warm upmore slowly in the spring, remainsomewhat cooler during the sum-mer, and retain heat longer in thefall. They lose only a small por-tion of their heat through theirwalls and bottom to the ground.

Their pumping systems are generally more robust thanabove-ground pools. Solar heat-ing, together with a pool cover,can greatly extend the swimmingseason for in-ground pools.

How does solar work with different pool types?

A solar heating system was installed in 1997 on this 7.3-m (24-ft.) round above-ground pool. It uses five south-facing 4.4-m2 (4-ft. x 12-ft.) collectors. “Solar is the best investment I’ve ever made,” says the owner. Pool owner: Mr. Bayard, Montréal Quebec. Photo courtesy of Heliocol Canada.

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15

Indoor poolsIndoor pools are usually con-structed of concrete and are partof the basic design and structureof the building they are in. Sincethey are less affected by outdoorweather conditions, they are par-ticularly suited to solar heating.

Unless an indoor pool is locatedso that sunshine falls on its sur-face for direct heat gain, it willrequire heating year-round. Solarheating systems for indoor poolsshould be designed by a solar pro-fessional. A pool cover should beused to reduce evaporation andsubsequent humidity problems.

Enclosed poolsUnlike an indoor pool, anenclosed pool is not intended foryear-round use, and the enclosureis not heated. But it can extendthe length of the swimming sea-son considerably. Even thoughheat loss is reduced by the enclo-sure, an insulated pool cover isstill advisable.

Pools can be enclosed within anaddition to a home, a separatestructure or an air-supported clearplastic tent. While all such poolswill benefit from direct sunlight,one that is enclosed in an air-supported plastic tent with goodsouthern exposure will receive the most light and heat.

Hot tubs andspasSolar collectors can also be usedfor heating hot tubs and spas.Although the water temperaturerequired is hotter than for swim-ming pools, typically 40°C (104°F),the volume and exposed surfacearea are smaller and therefore asmaller collector area is required.Glazed solar collectors are gener-ally required since they heat tohigher temperatures. Unglazedcollectors can be considered when a hot tub is allowed to drop to ambient temperaturewhen not in use.

The high water temperature cre-ates a large energy requirement,especially when a tub has beenrefilled with cold water. For exam-ple, a 1.5-m (5-ft.) diameter hot tub holds 2250 litres (500 gallons)and requires 87 kilowatt-hours of electricity during start-up, or about $6.55 if your rate is 7.5 cents per kilowatt-hour.Turbulence and air blowers addconsiderably to the rate of heatloss. They should be turned offwhen the tub is not in use.

Pool ProfileName of owner: Greg Henderson,Campbellville, Ontario

Pool size and type: 4.2-m x 8.4-m(14-ft. x 28-ft.) indoor pool

Year of solar installation: 1998

Solar collector array: Seven 4.4-m2 (4-ft. x 12-ft.) solar collectors and propane heater for wintertime

Owner’s comments:“When we moved into our newhome we didn’t realize how muchit would cost to heat the pool. We were paying $200 to $300 permonth for propane and that costwould be 50 percent higher today.

“Our solar heater now does all theheating from April to November,keeping the pool above 80°F [27°C]. The system paid for itself in two years! The only mainte-nance involved is draining thesystem and starting it up in thespring, which takes me a total ofabout half an hour per year. I alsothink it’s good for the environ-ment if I can avoid burningpropane whenever possible.

“I would recommend solar foroutdoor as well as indoor pools.”

16

Unglazed solarcollectors – Thecommon collec-tor for solar poolheating There are different types of“unglazed” solar collectors spe-cially designed for swimmingpools. Most of the collectors in use today are made of eitherrubber or ultraviolet (UV) stabi-lized plastic. Collectors typicallyconsist of many 6-mm (1/4-in.)tubes running the length of thecollector feeding into 38-mm (1-1/2-in.) or 51-mm (2-in.) diameter top and bottom headerpipes. The header pipes are con-nected to the adjacent collectorsto carry the main flow of water.

Plastic collectors are semi-rigidand become more pliable whenheated. Most have the riser tubeswelded adjacent to each other to form one solid surface. Othershave the tubes separated by an air gap that allows air to passbetween. This gap increases theheat loss from the panel, butmakes it more stable and lessprone to uplift during highwinds. Plastic collectors are 1.2-m (4-ft.) wide and come inthree standard lengths: 2.4-m (8-ft.), 3.0-m (10-ft.) or 3.7-m (12-ft.). They are connectedtogether with rubber couplingsand stainless steel clamps andtypically last 15 to 20 years in the Canadian climate.

The other material used forunglazed collectors is rubber.These collectors come in flexiblestrips that are assembled ontorigid header pipes during installa-tion. The strip form of the rubberallows the collector to be built to any practical length. These collectors tend to have lower efficiencies since there is a spacebetween riser tubes and becausethe tubes transfer heat slower due to their thicker walls. Headerpipes usually come in 0.3-m (1-ft.)sections that are connected usingan O-ring seal, lubricant and agrasping clip. These collectorshave a field life of up to 15 years.

What types of solar collectors are there?

17

Efficiency and rating of solar collectorsEach brand of solar collector hasbeen tested to determine its solarenergy collection efficiency, orthermal performance rating.Testing takes place at Canada’sNational Solar Test Facility and atthe Florida Solar Energy Center(FSEC) in the United States. The Canadian Solar IndustriesAssociation (CanSIA) publishestest results in their Directory ofApproved Products for collectors tested in Canada.

Solar energy collection efficiencyratings work in the followingway: an efficiency of 80 percentmeans the collector is able toabsorb 80 percent of the energyin the sunlight striking its surfaceand transfer it into the heatedpool water. Collector performanceis usually stated as BTU per squarefoot per day (BTU/sq. ft./d)according to the Florida SolarEnergy Centre (FSEC) standardtest. Some collectors may be ratedas high as 1000 BTU/sq. ft./d andothers as low as 700 BTU/sq. ft./d.

When purchasing a solar heater, it is important to consider thecollector efficiency. A smaller area of higher-performing collectors will provide the sameheating power as a larger area of lower-performing collectors. A system using panels with higher performance will maintaina higher pool temperature overthe summer.

Accordingly, expect the price of a lower-efficiency collector to beproportionally less than the priceof a higher-efficiency collector.

Factors affecting collector efficiency

Air TemperatureSolar collectors perform betterwith warmer air temperature. Asthe air cools, the collector losesmore heat to the air and transfersless heat to the pool water.

Flow RateMany manufacturers recommenda flow of 10 to 15 litres (approxi-mately 3 to 4 U.S. gallons) perminute per solar collector, whichmost pool pumps can easilyaccommodate. Slower flow rateswill slightly reduce the collector’sefficiency.

Wind on CollectorThe convective heat loss from the collector to the air around itincreases with increased exposureto wind.

Shading on CollectorCollectors shaded from the sun by trees or buildings will generally not add useful heat to the pool water unless the airtemperature is higher than thepool temperature.

Pool ProfileName of owner: Danny Ethier, St. Catharines, Ontario

Pool size and type: 5.5-m x 11-m(18-ft. x 36-ft.) in-ground, out-door pool

Year of solar installation: 1986

Size of collector array: Six 3-m2

(4-ft. x 8-ft.) solar collectors

Owner’s comments:“What I really like about the solarsystem is the efficiency and cost savings. My friends are installingsolar on their pools since the monthly gas bill is unnecessarywhen solar performs so well.

“I open my pool the end of Apriland swim to the second week ofOctober. When I open my pool inApril, with just three or four daysof good weather I can get mypool from 60°F to 78°F [16°C to 26°C]. I really get two moremonths of swimming than mostpool owners [that do not have aheater]. And I like to keep the temperature at 88°F to 90°F [31°Cto 32°C], which is comfortable formy kids and the neighbours’ kids.I use the pool cover at night tokeep the heat in.

“I installed solar originally withtwo other neighbours. My motherand two more neighbours havesolar now as well. Another friendwas offered a gas heater for freebut he bought solar instead. Evenmy pool dealer switched from agas heater to a heat pump tosolar.

“I’ve been pushing solar heating to any pool owners I know, and Iwelcome anyone to come andvisit my pool for a tour of how itworks.”

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Solar collector kitfor above-groundpoolsSome dealers carry specialty kitsfor above-ground pools. Thesetypically include a 1.2-m by 6.1-m (4-ft. by 20-ft.) unglazedsolar collector and the valves andtubing to connect to your poolfilter system. One collector willheat a 14-ft. round pool. The collector is usually placed on thelawn or propped up against thewall of the pool, facing south.

This kit is relatively inexpensive(around $300) and easily installedby the homeowner. Althoughthey tend to be lower priced, theyare also lower quality. They usu-ally have much less ultravioletinhibitor and less warranty cover-age. Most are only covered for100 percent of their value for oneyear. They have a field life of upto 10 years. Make sure the collec-tor area is sufficient for the size of your pool, as explained in the section on determining theright size for your solar heater on page 19.

Glazed solarcollectorsA glazed solar collector consists of copper tubes attached to ablack metal absorber plate (seeFigure 7). The whole collector ishoused within an insulated boxand covered with a sheet of glassto prevent heat loss. Glazed collectors operate at a higher temperature and are less affectedby heat loss due to wind and cool air temperatures. They aremore commonly used for solardomestic hot water heatingbecause of the higher tempera-tures they achieve.

Although not nearly as commonfor pool heating as unglazed,glazed collectors can be especiallyuseful for indoor pools that areused year-round or for outdoorpools in cool or windy climates.For year-round pool heating, aheat exchanger can be used totransfer heat to the pool waterand freeze-protect the solar collec-tors. Since glazed collectors aremore expensive (typically threetimes the cost of unglazed), theireconomics for solar pool heatingare less attractive.

Glazing

Insulation

Container

Header

Riser tubes

Absorber plate

Figure 7. Schematic of a glazed collector.

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19

Since a pool loses most of its heatfrom the surface, the size of asolar heater can be based on thepool’s surface area.

Most pools need a solar heatingsystem that is 50 percent to 75percent of the pool area. Forexample, a 5-m by 10-m (16-ft. by 32-ft.) in-ground pool has an area of 50-m2 (512-sq. ft.). Itwould typically need between 25-m2 (256-sq. ft.) and 37.5-m2

(384-sq. ft.) of solar collectors toadequately heat it. This could beobtained by using six to eight 4.4-m2 (4-ft. by 12-ft.) collectors.

If solar is the only heating sourceand a solar cover is routinelyused, as a general rule the collector area is typically at least50 percent of the surface area ofthe pool.

In some cases, pool owners maychoose to install a smaller solararea. If they want a shorter swim-ming season or plan to use abackup gas or electric heater, asmaller collector area will be capa-ble of providing most of the poolheating during the peak swim-ming months. Those using a fuelheater will find that a comple-mentary solar heater makes eco-nomic sense because of the sav-ings in fuel. And, smaller systemscan usually be enlarged, ifrequired, in the future.

The exact area of a collector willdepend on the amount of shadingon the pool surface, the roof ori-entation and tilt, the use of apool cover and the desired tem-perature. Other considerationsinclude the wind speed on thepool surface and solar collectors,any shading on the solar collec-tors and the length of swimmingseason.

A solar heating installer will com-bine the following design factorswith their knowledge of theregional climate and the poolowner’s particular operating needsto develop an appropriately sizedsolar heating system.

Shading on thepoolThe prime hours for solar poolheating, when the sun isstrongest, are between 10 a.m.and 5 p.m. Solar gain before andafter these times is much less crit-ical. A partially or fully shadedpool receives less passive solarenergy gain, and so needs moreexternal heat added from the poolheater. Shaded pools require alarger area of solar collectors tomaintain the pool temperature.

What size solar heater do I need?

Ottawa, Ontario.6.1-m x 12.2-m (20-ft. x 40-ft.) in-ground pool, eight 4.4-m2 (4-ft. x 12-ft.) solar collectors.Photo courtesy of Heliocol Canada.

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20

Location of solarcollectors –Orientation and tiltIdeally, solar collectors shouldface due south to intercept thesun’s rays at the most direct angle(see Figures 8 and 9). At midday,when the sun shines mostintensely, it is located due southin the sky. An orientation of up to45° to the east or west of duesouth will not affect performancedramatically. Collectors can evenbe placed on either a west- oreast-facing roof. However, west-facing is preferable since the high-er afternoon air temperatureimproves the collector’s performance.

The optimum tilt of the collector(the angle off horizontal) for sum-mer heating of pools is between15° to 40° for southern Canada.Normally, collectors are mounteddirectly on the roof since it is theleast expensive option.

If the roof slope is less than 15°or greater than 40°, any reductionin heating efficiency can beaccommodated by increasing the

collector area. Flat roofs generallyrequire a support rack of at least10° slope to ensure that the col-lectors drain properly and thatroof penetrations are avoidedwhere water can pool.

Use of a poolcoverAs mentioned in the section on managing pool energy use(page 10), the absence of an insulating pool cover dramaticallyincreases a pool’s heating require-ments. Pool owners who havedecided to forego a pool covermust install up to 50 percentmore solar collectors to make up for the extra heating need.

Pool ProfileName of owner: MargaretLouwerse, Oakville, Ontario

Pool size and type: 4.5-m x 9.0-m(15-ft. x 30-ft.) above-ground,outdoor pool

Year of solar installation: 1998

Solar collector array: Five 4.4-m2

(4-ft. x 12-ft.) solar collectors

Owner’s comments:“We built our pool in 1997 andfound the temperature just a littletoo cool for our young kids, evenusing a solar cover.

“We had solar installed and wecouldn’t believe the temperature shot up to 99°F [37°C] on the first weekend. We keep our pool at 86°F [30°C] and swimfrom the beginning of May to lateSeptember, and the kids can playin it all day now. Even with thecool weather this summer, ourpool was still comfortable.

“Solar was the best investment wemade that year – I never consid-ered using natural gas because of the energy and environmental consideration. Service was reliableand helpful.”

Figure 8. Diagram of the sun’s path.

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Figure 9. Typical orientations for solar collectors.

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21

Most collectorscan be mountedon your roofIn most cases, solar collectors areinstalled on the south-facing roofof a house, garage or shed. Theyhave a low profile and cleandesign allowing them to blend in with most traditional roofingmaterials. Unglazed solar collec-tors are lightweight, adding about 0.07 kilopascals (kPa) –1-1/2 pounds per square foot (psf) – to the roof, which is negligible compared to snowload, which can be 5 to 7 kPa(approximately 100 to 150 psf).

FastenersCollectors should be fastened to the roof with a high-qualityfastener. Some systems use a two-part cleat, which is lag bolted intothe sub-roof and sealed usingindustrial-grade caulking. UV-resistant synthetic webbing strapis laid across the body of collec-tors and held down with thecleat. Other brands fasten an aluminum bar to the roof, which is the mounting point for the collectors.

Modern mounting systems arevery reliable and completely seal the roof against leaking. Roof penetrations, however,should only be made on slopingroofs. Some manufacturers have wind-tunnel tested theirmounting systems up to speeds of 180 km/hr. Ask your installerfor details.

Flat roofs generally require asloped rack to ensure that:

a) water in the solar collectorsdrains properly, and

b) roof penetrations are avoidedwhere water can pool.

The rack can be weighted downor secured with a cable to ensureit is stable in winds.

Thermal expansionHot plastic collectors may expandas much as 2.5 cm over a 3-mlength (1 in. over 10 ft.). Theymust be carefully mounted to pre-vent damage from expansion andcontraction.

The surface beneath the panelsmust be smooth to prevent damage to the panels from sharpprojections in the roof and toavoid damage from rubbing whenthe panels contract and expand.Manufacturers have recommenda-tions on how to fasten the panelsto the roof and prevent damageby wind, snow and ice.

Piping installationThe piping used for solar heatersis standard PVC. The pipe is natu-rally white but can be painted to match the colour of your roofand exterior walls.

After the pipe iscut, the ends mustbe de-burred sincesmall shavings ofplastic can clogthe small fluidpassageways insome collectors.

The pipes should be arranged sothat they can be easily drained toprevent damage to the systemfrom freezing. On horizontal runs,the pipe should slope 1 cm forevery 5 m of length. In general,the pipe runs should be short anddirect.

Like the panels, plastic pipe willalso expand and contract, soallowances for that must be madeduring installation. A 30-m (100-ft.) length of plastic pipe mayexpand as much as 25 cm (10-in.).

It is important that all the collec-tors receive an equal flow ofwater. The standard technique, asshown on page 6, is to connectthem in parallel with the supplypipe feeding from the bottom.The water travels up the collectorsand is carried back to the poolthrough a return pipe at the top.The return flow pipe is thus diag-onally opposite to the supplypipe. For adequate flow, often a51-mm (2-in.) pipe is used for thesupply line and 38-mm (1-1/2 in.)is used for the return line.

How will my solar heater be installed and maintained?

Welland, Ontario.This 5-m x 10-m (16-ft. x 32-ft.) free-form pool isheated by six 4.4-m2 (4-ft. x 12-ft.) solar collectorsmounted on the garage. Photo courtesy of Daystar Energy.

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22

Collectors canalso be mountedon racksGround-mounted racks are usedwhen roof space or exposure isinadequate. They can be builtfrom pressure-treated or rot-resistant wood or from metal bars,and can also serve as a storageshed or as a weather-protectedarea for the pump, filter andother pool controls. A typical rack is shown in Figure 10.

Rack support posts should extendbelow the frost line, usually 1.2 m (4 ft.) below ground, andbe anchored in concrete. Theyshould be positioned so thatsnow and ice sliding off adja-cent roofs will not damage thecollectors.

Before building such a system,check to see if a building permitis required.

White Rock, British Columbia.Eight 4-m2 (4-ft. x 10-ft.) solar collectors on a wooden ground rack.Photo courtesy of Taylor Munro Energy Systems.

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Figure 10. Ground-mounted rack.

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23

You can choose amanual or auto-matic controlvalveSolar heating systems can beoperated either manually or auto-matically. A manual control valve(see Figure 11) is a simple three-way valve that is turned by handto divert water to the collectorsduring sunny weather. A goodautomatic controller, thoughmore expensive, can improveyour system’s performance by upto 30 percent. Using temperaturesensors, the controller divertspool water to the collectors onlywhen sufficient solar energy isavailable.

Figure 12 shows a typical auto-matic controller. An automaticcontroller should allow manualoverride and have a light thatshows you when it is on andwhen the collectors are circulat-ing. And, since you might wantthe pool cooler in midsummerthan earlier or later in the season,it should also allow you tochange the desired pool tempera-ture setting.

If your pool becomes too warm,circulating through the collectorsat night will cool the water. Someautomatic controllers include this option.

Activating thesystem isstraightforwardOnce the system is installed, thecollectors and piping should beinspected for leaks. The supplyand return lines should show a

temperature rise of about 5°C(9°F) during steady flow on asunny day.

A good solar pool heating systemmust also include the following:

• a vacuum-breaker air vent at high points in the pipingsystem for draining;

• isolation ball valves on thefeed and return lines;

• drain taps on the feed andreturn pipes at the low pointsin the piping system; and

• a swing-type check valve toprevent water from flowingbackward through the filterwhen the collectors drain.

Maintenance is easyA solar heating system shouldoperate problem-free. Only thecontroller has electrical and mov-ing parts. Controllers and sensorsshould last at least 10 years, if notthe lifetime of the collectors.

Due to breakdown by ultra-violet (UV) radiation, the plasticcollectors will degrade slowly andeventually produce leaks. It isbeneficial after 10 years to turnthe collectors over, exposing theshaded side. This can add years tothe life of the system. As well,some collectors are designed for simple repair using specialrubber plugs.

Special care mustbe taken withwinterizationIn the fall, prior to a serious riskof freezing weather, the solar

collectors must be completelydrained. Most of the water can bedrained into the pool by turningoff the pump. Any water remain-ing in the pipes should bedrained through taps located onthe low points of the feed andreturn pipes. Buried pipes willneed irrigation boxes and drainvalves. Alternately, the entire system can be blown out with a wet/dry vacuum.

Figure 11. Manual three-waydiverter valve.Courtesy of Pentair Pool Products

▼Figure 12. Automatic controller.Courtesy of Pentair Pool Products

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24

A solar pool heating system is amajor investment. Having yoursystem installed by a solar special-ist protects your investment andassures that the system will per-form as predicted. The contractorshould provide a one-year war-ranty for the labour, which coversleaks and damage to the roof.

Most solar contractors will offer a winter shutdown and springstart-up service, which includes a complete system checkup.

Selecting a solarcontractorSolar companies are generally listed in the yellow pages under“Solar Energy” or “Solar EnergyEquipment and Systems.” If there is no local contractor inyour area, contact the CanadianSolar Industries Association(CanSIA) at (613) 736-9077. Orvisit its Web site at www.cansia.ca,which includes a directory ofCanadian solar energy companies.In the province of Quebec, con-tact Énergie solaire Québec at (514) 392-0095. Many contractorsare willing to travel outside theirhome territory (within reason) to service customers.

For help on selecting a contractoror dealer, complete the consumerchecklist on page 26.

Selecting a solarcollectorWhen choosing a solar collector,consider the efficiency, durabilityand cost of the product. Ask thecontractor for references if youwould like confirmation on thequality of the product. A goodquality collector should last 15 years or longer.

If you are interested in the collec-tor efficiency rating, consult theCanSIA Directory of ApprovedProducts.

Understandingthe collector’swarranty Most solar collectors sold inCanada have a 10- to 15-year warranty. Some warranties willinclude repair or replacement offaulty collectors during the entirewarranty period. Others are limited warranties, pro-rated invalue after a number of years.Most warranties do not coverlabour or shipping costs.

For the warranty to take effect,the collectors must be installed,or the installation approved, by a qualified contractor. Freezedamage to the collectors is notcovered by most warranties sincethe collectors must be drained atthe end of the swimming season.

How do I make the best decision as a consumer?

25

Heat Pump

Parts $_________

Labour $_________

Additionalinstallationcosts

Example:

Electricallineinstallation(if separate) $_________

Others: $_________

$_________

Permit $_________

Totalinstallation costs $_________

Estimatedelectricitycosts over15 years(multiplyestimatedannualelectricitycosts* by 15)** $_________

Total heat pumpcosts after15 years $__________________

Natural Gas Heater

Parts $_________

Labour $_________

Additionalinstallationcosts

Example:

Natural gaslineinstallation(if separate) $_________

Others: $_________

$_________

Permit $_________

Totalinstallation costs $_________

Estimatednatural gascosts over15 years(multiplyestimatedannualnatural gascosts* by15)** $_________

Total naturalgas heatercosts after15 years $__________________

Propane Heater

Parts $_________

Labour $_________

Additionalinstallationcosts

Example:

Propanetankinstallation(if required) $_________

Propanelineinstallation

$_________

(if separate)

Others: $_________

Permit $_________

Totalinstallation costs $_________

Estimatedpropanecosts over15 years(multiplyestimatedannualpropanecosts* by15)** $_________

Total propaneheatercosts after15 years $__________________

Solar Heater

Parts $_________

Labour $_________

Additionalinstallationcosts

$0.00

Permit $_________

Totalinstallation costs $_________

Estimatedfuel costs over15 years

$0.00

Total solarheatercosts after15 years $__________________

Determining your potential costs

*If you have an existing pool heater, refer to your monthly fuel bills. If you are purchasing a heating system,ask your pool dealer what you could expect to pay for electricity or fuel over the course of a year.

**Please note that this calculation does not take into account electricity or fuel price increases.

26

Consumer checklist

To make an informed decision when purchasing a solar pool heater, there are questions you should ask andissues you should be aware of. Use this checklist to help you make an informed decision when selecting yourheater and solar contractor.

Selecting a solar contractor

Is the solar contractor listed with the Canadian Solar Industries Association? Yes ■■ No ■■

Can the contractor provide at least three references of systems that he/shehas installed? Yes ■■ No ■■

Can you make a site visit to any of the contractor’s previous installations? Yes ■■ No ■■

Has the contractor clearly outlined the type of servicing and maintenancecontract services he or she will provide? Yes ■■ No ■■

Has the contractor clearly outlined the terms of the contract you willbe signing? Yes ■■ No ■■

Are building permits required? Are plumbing and electrical inspections required? Yes ■■ No ■■

If so, who is responsible for arranging these?

Will the contractor be responsible for winterizing the system? Yes ■■ No ■■

Will you? Yes ■■ No ■■

Will the contractor provide maintenance or operational instructions? Yes ■■ No ■■

Selecting a solar collector

Can the contractor provide references for the solar collector sold to you? Yes ■■ No ■■

What is the collector’s performance rating from the CanSIA Directory ofApproved Products or the Florida Solar Energy Center?

What is the collector’s anticipated life span?

How much does the collector cost? $

Understanding the solar collector’s warranty

What is the length of the collector’s warranty?

Does the warranty include repair or replacement of faulty collectors duringthe entire warranty period? Yes ■■ No ■■

Does the warranty cover labour or shipping costs? Yes ■■ No ■■

Will the installation be completed or approved by a qualified contractor? Yes ■■ No ■■

27

Solar energy can be used to heatwater for a variety of uses. Inaddition to pool heating, a solardomestic hot water system can bepractical and cost-effective.

Any business or public facilitythat uses a large quantity of hotwater may also benefit from solarwater heating. Some examples of commercial applications inCanada include the following:

• public swimming pools;

• car washes the following;

• fish hatcheries;

• agricultural and foodprocessing; and

• parks and campgrounds.

Related publicationsSolar domestic hot water systemsare reviewed in Solar WaterHeating Systems: A Buyer’s Guide.To order a copy of this or otherpublications on renewable energy,please call NRCan’s toll-free lineat 1 800 387-2000. You can alsodownload a copy from our Website at http://www.nrcan.gc.ca/redi

Further information To learn more about solar waterheating, contact the following:

Renewable and Electrical Energy Division

Energy Resources BranchNatural Resources Canada580 Booth Street, 17th FloorOttawa ON K1A 0E4Fax: (613) 995-0087Web site:http://www.nrcan.gc.ca/redi

or

CANMETEnergy Technology BranchNatural Resources Canada 580 Booth Street, 13th FloorOttawa ON K1A 0E4Fax: (613) 996-9418Web site:http://www.nrcan.gc.ca/es/etb

Canadian Solar Industries Association

2415 Holly Lane, Suite 250Ottawa ON K1V 7P2Tel: (613) 736-9077Fax: (613) 736-8938Web site: http://www.cansia.ca

Énergie solaire Québec460, Sainte-Catherine Street West,Suite 701Montréal QC H3B 1A7Tel.: (514) 392-0095Fax: (514) 392-0952Web site: http://www.esq.qc.ca

To read more on solar water heating technologies or othertypes of renewable energy tech-nologies, visit the Web site ofNRCan’s Canadian RenewableEnergy Network (CanREN) athttp://www.canren.gc.ca.

Appendix 1: Other applications for solar water heating

28

British Thermal Unit(BTU)A unit of energy used to measurenatural gas. One thousand BTUsequals approximately one mega-joule and 1 million equalsapproximately one gigajoule.

Coefficient of performance (COP)The rating system used for heatpumps. It is the ratio of heat out-put to electricity input. A typicalrating falls between 3 and 5.

Fossil fuelA hydrocarbon fuel extractedfrom the earth’s crust, includingnatural gas and oil. Fuels derivedfrom natural gas and oil includepropane and gasoline.

Gigajoule (GJ)A unit of energy commonly usedto measure natural gas. Equals278 kilowatt-hours or approxi-mately 1 million BTUs.

Glazed solar collectorA glass-covered metal solar collector that operates at highertemperatures than unglazed collectors.

Greenhouse gasGases such as carbon dioxide(CO2) that absorb and trap heatin the atmosphere. The increasedproduction of these gases fromhuman activity is linked to accelerated warming of ouratmosphere, known as climatechange.

Heat pumpAn electric heater that extractsheat available in the air to heatpool water.

Kilopascals (kPa)A unit of pressure. Equals approx-imately 21 pounds per squarefoot.

Megajoule (MJ)A unit of energy. Equals approxi-mately 1000 BTUs.

Passive solar heatingSunlight absorbed into the poolwater causes natural heating.

Payback periodThe time it takes your savings inavoided fuel costs to equal thecapital cost investment of yoursolar heater, or how fast your sys-tem pays for itself in fuel savings.For example, a $4,500 solar heaterthat saves $1,500 per year in fuelhas a payback period of threeyears. If your pool has no heateror if you are replacing your con-ventional heater, the cost of thenew heater must be included inthe payback period.

Performance ratingThe effectiveness of the solar col-lector at converting the sun’senergy into heat. Expressed asmegajoules per square metre perday (MJ/m2/d) or BTU per squarefoot per day (BTU/sq. ft./d).

Solar blanketA floating polyethylene materialthat insulates the pool surfaceand allows light to pass throughinto the pool.

Solar collectorA device that absorbs solar energyand converts it into usable heat.

Thermal blanketA floating foam cover that insu-lates well but does not allow lightto pass through it into the pool.

Unglazed solar collectorA plastic or rubber solar collector that operates at pool temperatures.

Appendix 2: Glossary

29

Reader Survey

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