A Consumer’s Guide

Heat YourWater with the Sun

Bringing you a prosperous future where energy is clean, abundant, reliable, and affordable

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Background

What is solar heating? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2What are the basic components of a solar thermal system? . . . . . 2How have solar systems improved? . . . . . . . . . . . . . . . . . . . . . . . . 5

Investing in solar thermal technologies

Why should I invest in a solar thermal system? . . . . . . . . . . . . . . 6How much will your solar heating system help the

environment? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6Is my home a good place for a solar heating system? . . . . . . . . . . 6How big should my solar thermal system be, and which

features should I look for? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7How much money will my solar thermal system save, and

how much will it cost? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9How can I finance the cost of my solar thermal system?

Are there incentives? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11What are the maintenance issues and repair costs for a solar

thermal system? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Selecting a solar heating contractor

Who sells and installs solar thermal systems? . . . . . . . . . . . . . . 13How do I choose among solar thermal system providers? . . . . . 13How do I choose among bids? Is the least expensive the

best deal? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Before you put solar heating to work

Do I need a conventional system as a backup? . . . . . . . . . . . . . . 15Will I need any permits or inspections? . . . . . . . . . . . . . . . . . . . . 16What about insurance? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16Will I need warranties? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16Will I need a maintenance agreement? . . . . . . . . . . . . . . . . . . . . 16

Getting help . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Contents

Cover photo: The people living in this house enjoy hot water that isheated with a solar thermal system. (Courtesy of Industrial Solar Technology/PIX12964)

Photo opposite: Flat-plate solar collectors heat this pool in Oregon.The unglazed polymer collectors sit on top of a flat roof and provideshade to the patio below.

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Would you like to learn more about how the sun can help meet yourhome’s heating needs without straining your budget?

Today’s solar heating systems not only keep swimming pools warm—they can also heat much of your home’s water and interior space. Theirpopularity is increasing, for several reasons. Solar heating systems are reliable, adaptable, and pollution-free because they use renewable energyfrom the sun. Many systems include sleek, attractive, low-relief collectorsthat people often mistake for skylights.

Did you know that solar heating systems work well in many different climates? Some applications, such as pool heating, are widely cost-effective today. The cost-effectiveness of other applications depends onspecific circumstances, such as the type and cost of your usual source ofenergy. Today, special financing is available to help you purchase the system that’s right for your home.

If you’d like to find out more about solar heating for your home or pool,this booklet is a good place to start. Here, you’ll learn how solar heatingsystems work, how they’re used, their benefits, and how to purchase oneyourself. Please note, however, that this booklet isn’t a technical guide to designing and installing a system. For that, you’ll need to consult anexperienced solar heating contractor; see “Getting help” in this booklet for more information.

A solar heating system is a substantial but rewarding investment. It canreduce your monthly heating bill while helping to protect our environ-ment. Being informed and planning carefully will ensure that you’ve chosen the right system for you and your family.

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What is solar heating?

Solar heaters, or solar thermal systems, provide environmentallyfriendly heat for household water,space heating, and swimming pools.The systems collect the sun’s energyto heat air or a fluid. The air orfluid then transfers solar heatdirectly or indirectly to your home,water, or pool.

Solar water heaters, sometimescalled solar domestic hot-water systems, may be a good investmentfor you and your family. Solar waterheaters are cost effective for manyapplications over the life of the system. Although solar waterheaters cost more initially than conventional water heaters, the fuelthey use—sunshine—is free. Solarheating technologies can be used in any climate. To take advantage of solar energy, you usually need to

have an unshaded area that facessouth, southeast, or southwest, such as a roof. In some cases, a solarprofessional may recommend west-facing roofs for solar collectors.

The type of system you choose,including the type of collector and whether it is active or passive,depends on several factors. Theseinclude your site, the climate youlive in, installation considerations,cost, and how you would like yoursolar heating system to be used.

What are the basiccomponents of a solarthermal system?

Solar water heaters and solar spaceheaters are made up of solar collec-tors, and all systems except poolheaters have some kind of storage.In pool systems, the swimming poolitself is the storage, and the pool’sfiltration pump circulates the poolwater through the collectors.

Active systems also have circulatingpumps and controls; passive sys-tems work without this addedequipment.

Three types of solar collectors areused for residential applications:flat-plate, integral collector-storage(ICS), and evacuated-tube collectors.

Flat-plate collectors like the oneshown on page 3 are the most common type. Glazed flat-plate collectors essentially are insulated,weatherproofed boxes that containa dark absorber plate under one or more glass or plastic (polymer)

Background

Simplified representation of a solar water-heating system

Roof-top collector

Solar-heated tap water

Solar storage tank/ conventional backup heater

Swimming pools and your home may also be heated using solar energy

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covers. Unglazed flat-plate collec-tors are simply a dark absorberplate, made of metal or polymer,without a cover or enclosure.Unglazed flat-plate collectors madefrom polymer materials are typicallyused in solar pool-heating systems.See the photos on pages 1 and 7and the diagram on page 9 forexamples.

Integral collector-storage systems,also known as ICS or “batch” sys-tems, are made of one or moreblack tanks or tubes in an insulated,glazed box. Cold water first passesthrough the solar collector, whichpreheats the water, and then con-tinues to the conventional backupwater heater. ICS systems are sim-ple, reliable solar water heaters.However, they should be installedonly in mild-freeze climates becausethe outdoor pipes could freeze inseverely cold weather.

Evacuated-tube solar collectorsare usually made of parallel rows oftransparent glass tubes. Each tubecontains a glass outer tube andmetal absorber tube attached to a fin. The fin is covered with a

coating that absorbs solar energywell, but which inhibits radiativeheat loss. Air is removed, or evacuat-ed, from the space between the glasstubes and the metal tubes to form a vacuum, which eliminates conduc-tive and convective heat loss. In theUnited States, evacuated-tube col-lector systems are used most fre-quently in commercial applications.

Most solar water heaters require a well-insulated storage tank.Solar storage tanks have an addi-tional outlet and inlet connected to and from the collector. Activesolar systems usually include a storage tank along with a conven-tional water heater. In two-tank systems, the solar water heater preheats water before it enters theconventional water heater. In a one-tank system, like the one shown on page 4, the backup heater iscombined with the solar storage in one tank.

Active solar water heaters usepumps to circulate water or a non-freezing heat-transfer fluid fromstorage tanks through the collec-tors. Active systems are usually

Glazed flat-plate collector

Inlet connection

Glazingframe

Enclosure

Flow tubesGlazing

Outletconnection

InsulationAbsorber plate

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more expensive than passive systems, but they are also usuallymore efficient.

Direct circulation systems use apump to circulate household waterthrough the collectors and into thehome; they work well in climateswhere it rarely freezes. Indirectcirculation systems use pumps to circulate a non-freezing heat-transfer fluid through the collectorsand a heat exchanger. This heatswater that then flows into thehome. Indirect systems are popularin climates prone to freezing temperatures.

Passive direct solar waterheaters, like the one shown onpage 5, move household water or a heat-transfer fluid through thesystem without using pumps orelectricity. Passive systems workduring power outages, but they

should not be used in climateswhere temperatures often go belowfreezing. Passive systems are typical-ly less expensive to purchase andmaintain than other types of solarsystems. They are also inherentlymore reliable and may last longer.However, passive systems are notusually as efficient as active systems.

ICS passive solar systems may be best in areas where temperaturesrarely go below freezing. They arealso good in households with significant daytime and eveninghot-water needs.

Thermosyphon systems workbecause water flows through thesystem when warm water rises ascooler water sinks. In this system,the collector must be installedbelow the storage tank so thatwarm water will rise into the tank.These systems are reliable, but

Active indirect one-tank system

Collectorsensor

Collector

Controller

PumpAir

eliminator

Expansion tankPressure gauge

Fill/drainassembly

Air vent

Drain

Drain

Element

Cold water in

Hot water out

P/T reliefvalve

Heatexchanger

Tank

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contractors must pay careful atten-tion to roof design because thewater in the storage tank is heavy.Thermosyphon passive solar sys-tems are usually less expensive thanactive systems, but more expensivethan ICS systems.

How have solar systemsimproved?

Since the early 1970s, the efficiencyand reliability of solar heating sys-tems and collectors have increasedgreatly and costs have dropped.Improvements to materials, a ratingsystem for consumers, and moreattractive designs have all helped to make systems more successful.

Low-iron, temperedglass is now usedinstead of convention-al glass for glazing.Improved insulationand durable selectivecoatings for absorbershave improved effi-ciency and helped toreduce life-cycle costs.

The Solar Rating and CertificationCorporation (SRCC)and the Florida SolarEnergy Center (FSEC)certify and rate solarthermal systems andequipment. SRCCevaluates product reliability and ratesthe performance ofsolar water-heatingsystems by subjectingthem to technicalreviews. SRCC has a

directory of certified systems on its Web site along with system performance ratings. FSEC publishessimilar information specific toFlorida that is useful in other stateswith similar climates. See the“Getting help” section for contactinformation.

The appearance of the systems hasalso improved. Today’s collectorscan usually be mounted flush withthe roof for a streamlined systemthat looks like skylights. Unglazedpolymer collectors for solar poolheating are now available in terracotta colors as well as black, sohomeowners can choose the colorthat will best match their home.

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Passive direct system

Freeze preventionvalve

From collector

To collector

ICS Collector

Drain valve

Check valve

Isolation valve

Pressure/temperaturerelief valve

Pressurerelief valveShutoff

valve

Dip tube

Top element

Water heater tank

Hot water out

Cold water inThree-way ball valve

Bottom element

Drain

Drain valve

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Why should I invest in a solar thermal system?

The first question many people askwhen considering a home expenseis, “How much will it cost?” Theanswer depends on the type of sys-tem, how you want to use it (wateror pool heating, for example), andyour geographic location. But mostsolar thermal systems cost between$2,000 and $4,500. Although this is usually more than the cost of aconventional gas or electric system,today’s solar heating systems arecost competitive when you consideryour total energy costs over theentire life of the system.

Your monthly gas or electricity billswill usually be lower and more predictable for as long as you ownthe house. Also, solar heating sys-tems will insulate you from risingfossil fuel costs and protect youfrom fuel-price inflation over time.Investing in a solar thermal systemcould also increase the resale valueof your home. Often, the entire initial cost of the system can berecovered when you sell your property. In addition, you will be earning an annual 6% to 25%tax-free rate-of-return on yourinvestment, depending on howmuch hot water you use and howmuch energy you save.

Another important reason to investin solar systems may be less tangi-ble. When you purchase a solarheating system, you support tech-nologies that are good for the environment. You are making a

conscious, responsible decision tohelp reduce harmful emissions fromfossil fuels, while maintaining yourquality of life.

How much will your solarheating system help theenvironment?

Depending on the type of conven-tional fuel used, replacing an elec-tric water heater with a solar heatercan offset the equivalent of 40% to100% of the carbon dioxide emis-sions of a modern passenger car.

Carbon dioxide traps heat in ouratmosphere, contributing to thegreenhouse effect, which alters our planet’s climate and ecologicalsystems. Using solar energy in placeof nonrenewable fuels may alsoreduce nitrous oxides and sulfurdioxides, which are components of smog.

Is my home a good place for a solar heating system?

The first consideration when build-ing a solar thermal system is thesite. If your site has unshaded areasand generally faces south, it is agood candidate for a solar thermalsystem. A professional installer canevaluate your roof as a location forcollectors. If your roof doesn’t haveenough space, you can also installthe system on the ground. Pleaserefer to the system-sizing section ofthis booklet for more informationon space requirements. The amountof sun that your site receives, how often temperatures dip below

Investing in Solar Thermal Technologies

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freezing, and other factors will also affect the type of solar heatingsystem you choose.

Before getting under way, you needto consider your homeowners association rules and neighbor-hood bylaws, also known as codes,covenants, and restrictions (CC&Rs).In Arizona, California, and Florida,state laws prohibit CC&Rs thatrestrict solar system installations.Nine other states have similar lawsbarring regulations that unreason-ably limit solar energy use inplanned communities. Some citiesand counties have ordinances orrequire permits for home improve-ment construction, including solarsystem installation.

How big should my solarthermal system be, and whichfeatures should I look for?

Some of the answers to questionsabout system size and featuresdepend on how you plan to use the solar system. Here, you’ll findgeneral information on sizing systems for water heating, swim-ming pools, and space heating. To locate more specific information,please see “Getting help” onpage 17.

Sizing a solar thermal system for heating domestic water

Just as conventional water heaterscome in different sizes, so do solarwater heaters. Sizing your solar

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water heater involves determiningthe total collector area and storagevolume you need to meet 90% to100% of your household's hot waterneeds during the summer. Solar-equipment experts use worksheetsand computer programs to helpdetermine system requirements and collector sizing.

Contractors usually follow a guideline of about 20 square feet(2 square meters) of collector areafor each of the first two familymembers. For every additional per-son, add 8 square feet (0.7 squaremeters) if you live in the Sun Beltarea of the United States, or 12 to14 square feet (1.1 to 1.3 squaremeters) if you live in the northernUnited States.

For active systems, the size of thesolar storage tank increases with the size of the collector—typically1.5 gallons per square foot of collec-tor. A small, 66-gallon system isusually big enough for one to threepeople; a medium-size, 80-gallonsystem works well for a three- orfour-person household; and a large,120-gallon system is appropriate for four to six people.

In recent years, homebuilders havebegun including solar water heatingsystems as standard features insome subdivisions. The systems arethe same size for every home, andthey all work equally well. However,large families with greater hot-waterdemand find that a smaller percent-age of their hot water is provided bythe solar energy system.

Sizing a solar thermal system for heating swimming pools

Heating your swimming pool withsolar energy requires a collector that is 50% to 100% of the surfacearea of your pool. Your geographiclocation and other factors deter-mine the exact size.

For example, a 15-by-30 foot swimming pool in Florida typicallyrequires a collector that equals100% of the pool’s square footage,which translates to 450 square feetof unglazed flat-plate collectors.This is because many Florida swim-ming pool owners use their poolsyear round. In contrast, in northernCalifornia, most pools are used only6 to 8 months per year, so systemsare typically sized at 60% to 70% of the pool’s surface area.

In general, adding more squarefootage lengthens the swimmingseason and allows owners to use thepool in colder weather. A pool coveror blanket reduces heat loss andhelps maintain warm temperaturesfor a longer period.

Sizing a solar thermal system for space heating

In contrast to solar water heating,solar space heating usually requiresa larger, more complicated system.Space-heating systems have to storeheat for use when solar energy isleast available and your house iscoldest—at night and during thewinter months. Solar space-heatingsystems are usually combined withwater heating, and they are sized to accommodate both uses.

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The amount of solar collector areaneeded to heat your home dependson many factors. These include theavailable solar energy, collector effi-ciency, local climate, and heatingrequirements. Heating requirementsare based on insulation levels, thehouse’s airtightness, and the life-style of the residents. Generally, thearea of solar collector is about equalto 10% to 30% of the floor area ofthe house.

How much money will mysolar thermal system save,and how much will it cost?

Your savings depend on how yoursolar system will be used, as well as

the size and type of your system.Other factors can include the climate, the contractor, and the system rating. Your state may offersolar rebates or other incentivesthat will reduce costs.

Savings and costs for solardomestic water heating

Solar heating systems can save you money in the long run. FSECstudied the potential savings toFlorida homeowners who use common water-heating systems,including solar, in comparison to electric water heaters. FSECundertook this study because theinitial installed cost of a solar water

Solar pool-heating system

Collector

Sensor

Pump

Filter

Automatic control box

D

B

EAGate valve

Warm water returns to pool

Pool water in

C

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Vacuum breaker/auto-air reliefA Check valve

B Gate valve

C Chlorinator (if applicable)

D Drain valve

E Bypass valve

F Booster pump(if necessary)

Fossil fuel heater (if applicable)

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heater is higher than that of a gasor electric water heater. FSEC want-ed to explore costs and savings overtime, beyond the initial installationperiod. The study found that solarwater heaters offered the greatestpotential savings. Annual utilitycosts for solar water heaters were50% to 85% lower than those forelectric water heaters.

The cost and benefit of purchasinga solar water heater vary fromregion to region, so check costs inyour area. Depending on the priceof the conventional fuel, a solarwater heater can be more economi-cal over the life of the system thanheating water with electricity, fueloil, propane, or even natural gas.That’s because the fuel—sunshine—is free.

However, at historically low pricesfor natural gas, the total cost ofowning a solar water heater with a backup natural gas heater may be more expensive than owning a natural gas heater alone.Nevertheless, as natural gasbecomes more costly and its avail-ability more volatile, solar waterheaters become more economical.Solar water heaters are often quitecost-competitive in new homes.

In many places in the United States, homebuilders choose electric water heaters because theyare easy to install and relativelyinexpensive. Research shows thatthe average household with an electric water heater spends about

25% of its home energy costs onheating water.

If you are building a new home or refinancing because of a major renovation, the economics are evenmore attractive. Including the priceof a solar water heater in a new 30-year mortgage usually amountsto between $13 and $20 per month.The federal income tax deductionfor mortgage interest attributable to the solar system reduces that by about $3 to $5 per month. So, if your fuel savings are more than $15 per month, the solar invest-ment is profitable immediately. On a monthly basis, you are savingmore than you are paying.

Savings and cost for solarswimming pool heating

A solar heating system for your pool usually costs between $3,000and $4,000 to buy and install. Thisprovides a payback of between 1.5 and 7 years, depending on thecost of the fossil fuel your systemreplaces. The actual cost and pay-back depends on your site, the typeof system you choose, financing,and the length of the pool season.

Often, a payback cannot even becalculated, because many peoplechoose not to heat their pool at all,given the extra $300 to $600 ontheir energy bill. A solar systemallows these people to swim in apool that was previously too costlyto heat and too cold to use.

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Savings and cost for solar space heating

The cost of a solar space-heatingsystem depends on many factors,including the size of your house,how airtight it is, how much ofyour heat will be supplied with aconventional backup, the systemyou choose, and your site. In general, solar space-heating systemscan provide 40% to 60% of yourspace-heating needs. These systemsare most economical for consumerswho would otherwise be heatingwith electricity, rather than withnatural gas or other fuels.

But solar space heating is neededmost when sunlight is least available, during the winter and at night—and needed least when sunlight is most available, duringthe summer and the daytime. Sotoday’s solar technologies are notlikely to be a cost-effective solutionfor active solar space heating inmost homes. However, a good alter-native is to simply to use passivesolar building techniques. See theEERE Web site, www.eere.gov/solar,for more information.

How can I finance the cost of my solar thermal system?Are there incentives?

Financing

Financing the cost of your solarthermal system is not as tricky as it may seem. Although some special programs are available tohelp you purchase solar thermaltechnologies, most of the financingoptions are familiar ones.

One common way to finance a solarsystem is through your mortgage orthrough a home-equity loan securedby your home. Mortgage loans offer lower interest rates and longerpay schedules than conventionalbank loans, and interest on yourmortgage loan is tax-deductible.Financing your system when youapply for your mortgage—whetherbecause you are building or refi-nancing—can make the applicationprocess simpler and less costly.

Conventional bank loans are another way to finance your solarsystem. However, your system is along-term investment; this shouldbe reflected in the pay schedule for the loan. Look for longer terms andlower interest rates, which will helpkeep your solar thermal systemaffordable.

Incentives

Many states have incentives forbuying solar technologies. Checkwith your state or local energyoffice or your state departments of revenue or finance for informa-tion. Some electric utilities offerrebates to customers who installsolar energy equipment becausethese installations help utilitiesreduce energy use during times of high demand.

You can also check the NationalDatabase of State Incentives forRenewable Energy (DSIRE). DSIRE is prepared by the North CarolinaSolar Center. It provides informa-tion on financial and regulatoryincentives to promote renewableenergy technologies. For informa-tion, see “Getting help” on page 17.

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What are the maintenanceissues and repair costs for a solar thermal system?

The costs of maintaining your solarthermal system depend on the typeof technology you choose and howoften temperatures in your area fallbelow freezing. Properly maintainingyour system will keep it runningsmoothly.

Passive systems do not requiremuch maintenance. For active systems, discuss the maintenancerequirements with your systemprovider and consult the systemowner’s manual. Plumbing andother conventional componentsrequire the same maintenance asconventional systems. Glazing

may need to be cleaned in dry climates where rainwater does not provide a natural rinse.

Regular maintenance on simple systems can be as infrequent asevery 3 to 5 years, preferably by a solar contractor. Systems withelectrical components usuallyrequire a replacement part or twoafter 10 years. Simple, regular sys-tem checks can also be effective. For example, one easy way to check the system is to carefully feel the hot-water pipes going into the storage tank after the system has been working on a clear, warm day. If the pipes are hot, your system is working properly.

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Selecting a solar heating contractorWho sells and installs solar thermal systems?

Depending on your area, the simplest way to find a solar thermal systems contractor is tolook in the yellow pages under“Solar Energy Equipment andSystems—Dealers.” Most of the listings will probably be for solarwater heating, photovoltaic (solarelectric), or electric systems contractors.

You can also contact your utilitycompany to get information on recommended vendors, or searchon the Internet for solar water heating, solar pool heating, or solar space heating, depending onthe application you are interested in installing.

Your state may have an active chapter of the Solar EnergyIndustries Association (SEIA), atrade association of contractors, distributors, and manufacturers. See “Getting help” for contact information.

How do I choose among solar thermal systemproviders?

One way to choose a contractor is to check your list of potential companies for the ones nearest you. Ask them what products andservices they offer. Here are a fewquestions you might want to askpotential vendors.

Has your company installed solar thermal systems for solarwater heating, pool heating, or space heating?

Choose a company that has experience installing the type ofsystem you want and servicing the applications you select.

How many years of experiencedoes your company have withsolar heating installation?

Obviously, the more experience the better. A business that has been working with these systemsfor a long time will be more professional, know more about current technologies and recentadvances, and be less likely to make costly mistakes. Request a list of past customers who can provide references.

Is your company licensed?

Having a valid plumber’s or solarcontractor’s license is required insome states for solar thermal system installation. You can confirm licensing by contactingyour state contractor licensingboard. Local requirements may also include a local contractor’slicense. Call your city and countyfor information on other requiredlicenses.

For you to obtain certain rebates,your contractor may have todemonstrate special knowledge

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about solar installations throughone or more of the following:

• Possession of a solar contractorspecialty license issued by alocal building jurisdiction

• Certification in solar thermalsystems by a group such as thestate chapter of SEIA

• A letter from the solar heatingmanufacturer that indicatesthat the installer has the neces-sary experience and training toinstall solar systems.

Does your company have anypending or active judgments or liens against it?

As with any project that requires a contractor, due diligence is recommended. Your state contractorlicensing board can tell you aboutany complaints against state-licensed contractors. The BetterBusiness Bureau is another goodsource for such information.

How do I choose among bids?Is the least expensive the best deal?

It is usually a good idea to get morethan one bid for installation of yoursolar system. Make sure that all thebids you receive are based on thesame information and require-ments. For example, comparing abid for a system mounted on yourroof with a bid for one mounted on the ground would not tell youhow the two bids compare—itwould probably tell you more abouthow the two types of installationscompare.

One solution is to ask for bids on systems certified by the Solar Rating and CertificationCorporation (SRCC). If possible,have each bid specify system typeand size, energy output, mainte-nance requirements, and cost. Cost should include having the system installed and getting it up and running, as well as the cost of hardware, permits, sales tax, and warranties.

A system warranty is crucial in comparing bids. A solar rebate program may require a writteninstallation warranty, for example a 2-year parts-and-labor warranty in addition to manufacturers’ warranties on system components.The company may offer other,longer warranties, particularly on the collectors. However, solar systems are more than collectors;active systems include electroniccomponents, pumps, valves, andwiring. Make sure you know whatyour warranty covers and that the company stands behind the full warranty.

If you have several bids, you maywonder if the lowest bid is the best deal. Sometimes it is not. Asolar thermal system installer is in business to make money; over-head and operating expenses mustbe covered. A low price could be a sign of inexperience, or of a company without staying power.Contractors that expect to stay inbusiness must charge enough tocover their products and servicesplus make a fair profit. Price is not the only consideration.

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Do I need a conventionalsystem as a backup?

Whether you need a backup systemfor your solar thermal systemdepends largely on the type of system you choose and where youlive. Solar water-heating systemsalmost always require a backup system for cloudy days and times of increased demand. This backupsystem is typically a conventionalgas or electric water heater and may already be part of the solar system package. It may also be part of the solar collector, such asrooftop tanks with thermosyphonsystems. For example, an integralcollector-storage system (ICS) may be packaged with an instanta-neous gas water heater for backup.

The ICS system stores hot water inaddition to collecting solar heat,and the instantaneous water heaterprovides hot water when solar heatis not available.

Most people do not need or use a backup heater with solar poolheaters. In freeze-prone climates,solar pool heaters are used mainlyin summer. Spas or hot tubs are an exception. Spa owners may usetheir solar system to heat both thepool and the spa, but will use abackup heater to get the spa to ahigher temperature. In climateswhere it rarely freezes, pool heatersmay be used year-round.

If you decide to install solar thermalspace heating, you will almost

Before you put solar heating to work

Rooftop collectors can be installed on most roofing materials

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certainly need a backup system.Space-heating systems require alarge collector area, significant storage volume, and a highly efficient building envelope to produce enough energy to heatyour home at night and during the winter. Solar space heating usually provides 40% to 60% ofyour home’s space-heating needs. A backup system ensures that your house is comfortably warmduring power outages, cold snaps,and extended cloudy periods. Many building codes and mortgagelenders require a conventional backup space heater.

Will I need any permits or inspections?

If you live in a community with a homeowners association, check to see if any approvals, permits, or inspections are required. Alwaysobtain the necessary approvals from the association before begin-ning construction. Homeownersassociations, towns, cities, andcounties usually have a legal rightto require approval before building.However, some states have solar-rights laws that may apply ifapproval is denied.

You will probably need to obtainpermits from the building depart-ment that has jurisdiction in yourstate, county, or city. Plumbing,building, and electrical permits maybe required. These permits typicallyrequire a final inspection after thesystem has been installed. Checkwith your solar heating system contractor to find out whether

the price of obtaining permits andinspections is included in the bidand final cost estimate.

What about insurance?

If you are buying a solar heatingsystem for your home, your regularhomeowners insurance shouldcover your needs. However, if insurance coverage becomes anissue, please refer to “Getting help”on page 17.

Will I need warranties?

Warranties are an important factorin the bidding process and animportant aspect of the system you choose. Make sure you knowthe warranties that your systemmanufacturer and installer offer for your equipment and hardware,as well as parts-and-labor war-ranties. Check to make sure themanufacturer can provide supportand supplies if the installer is not available.

You can usually obtain a full-systemwarranty plus parts-and-labor for at least 1 to 3 years. This means you will not be responsible for system problems covered by thewarranty in the first year or two of system operation.

Will I need a maintenanceagreement?

A maintenance agreement may be part of your warranty. Have the contractor prepare a schedule of required or recommended maintenance before you purchaseyour system.

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American Solar Energy Society (ASES)2400 Central Avenue, Suite G-1Boulder, CO 80301www.ases.orgPhone: (303) 443-3130Fax: (303) 443-3212E-mail: ases@ases.org

Database of State Incentives for Renewable Energy (DSIRE)www.dsireusa.org

Florida Solar Energy Center (FSEC)Public Affairs Divisionwww.fsec.ucf.eduPhone: (321) 638-1015 Fax: (321) 638-1010E-mail: info@fsec.ucf.edu

National Renewable Energy LaboratorySolar Energy Technology Programwww.eere.energy.gov/solar.html

Solar Benefits Model Softwarewww.eere.energy.gov/solarbuildings/sbm.html

Solar Energy Industries Association (SEIA)1616 H Street NW, 8th FloorWashington, DC 20006-4999www.seia.orgPhone: (202) 628-7745Fax: (202) 628-7999

Solar Rating and CertificationCorporation (SRCC)c/o FSEC1679 Clearlake RoadCocoa, FL 32922-5703www.solar-rating.org(See standards document OG-300)Phone: (321) 638-1537Fax: (321) 638-1010E-mail: srcc@fsec.ucf.edu

Getting Help

Solar thermal technologies work in a variety of climates

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About the Office of Energy Efficiency and Renewable Energy

A Strong Energy Portfolio for a Strong AmericaEnergy efficiency and clean, renewable energy will mean a stronger economy, acleaner environment, and greater energy independence for America. By investing intechnology breakthroughs today, our nation can look forward to a more resilienteconomy and secure future.

Far-reaching technology changes will be essential to America's energy future.Working with a wide array of state, community, industry, and university partners,the U.S. Department of Energy's Office of Energy Efficiency and Renewable Energyinvests in a portfolio of energy technologies that will:

• Conserve energy in the residential, commercial, industrial, government, andtransportation sectors

• Increase and diversify energy supply, with a focus on renewable domestic sources• Upgrade our national energy infrastructure • Facilitate the emergence of hydrogen technologies as vital new "energy carriers."

The Opportunities

Biomass Program—Using domestic, plant-derived resources to meet our fuel,power, and chemical needsBuilding Technologies Program—Homes, schools, and businesses that use lessenergy, cost less to operate, and, ultimately, generate as much power as they useDistributed Energy & Electric Reliability Program—A more reliable energyinfrastructure and reduced need for new power plantsFederal Energy Management Program—Leading by example, saving energyand taxpayer dollars in federal facilitiesFreedomCAR & Vehicle Technologies Program—Less dependence on foreignoil, and eventual transition to an emissions-free, petroleum-free vehicleGeothermal Technologies Program—Tapping the Earth's energy to meet our heat and power needsHydrogen, Fuel Cells & Infrastructure Technologies Program—Paving theway toward a hydrogen economy and net-zero carbon energy futureIndustrial Technologies Program—Boosting the productivity and competitivenessof U.S. industry through improvements in energy and environmental performanceSolar Energy Technology Program—Utilizing the sun's natural energy to generate electricity and provide water and space heating Weatherization & Intergovernmental Program—Accelerating the use of today'sbest energy-efficient and renewable technologies in homes, communities, and businessesWind & Hydropower Technologies Program—Harnessing America's abundantnatural resources for clean power generation

To learn more, visit www.eere.energy.gov

The National Renewable Energy Laboratory,a DOE national laboratory, produced this Consumer’s Guide for:

U.S. Department of EnergyOffice of Energy Efficiency and Renewable Energy1000 Independence Avenue, S.W.Washington, D.C. 20585

December 2003 • DOE/GO-102003-1824