DOE Consumers Guide to Hot Water

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DOE Consumers Guide to Hot Water Powered By Docstoc
					                          A Consumer’s Guide

Heat Your W with theSun

Bringing you a prosperous future where energy is clean, abundant, reliable, and affordable
       What is solar heating? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
       What are the basic components of a solar thermal system? . . . . . 2
       How have solar systems improved? . . . . . . . . . . . . . . . . . . . . . . . . 5

 Investing in solar thermal technologies
       Why should I invest in a solar thermal system? . . . . . . . . . . . . . . 6
       How much will your solar heating system help the
           environment? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
       Is my home a good place for a solar heating system? . . . . . . . . . . 6
       How big should my solar thermal system be, and which
           features should I look for? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
       How much money will my solar thermal system save, and
           how much will it cost? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
       How can I finance the cost of my solar thermal system?
           Are there incentives? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
       What 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? . . . . . . . . . . . . . . 13
       How do I choose among solar thermal system providers? . . . . . 13
       How 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? . . . . . . . . . . . . . .                     15
       Will I need any permits or inspections? . . . . . . . . . . . . . . . . . . . .              16
       What about insurance? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .      16
       Will I need warranties? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .    16
       Will I need a maintenance agreement? . . . . . . . . . . . . . . . . . . . .                 16

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

     Cover photo: The people living in this house enjoy hot water that is
     heated 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 provide
     shade to the patio below.

  Heat Your W with the Sun
Would you like to learn more about how the sun can help meet your
home’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. Their
popularity is increasing, for several reasons. Solar heating systems are
reliable, adaptable, and pollution-free because they use renewable energy
from the sun. Many systems include sleek, attractive, low-relief collectors
that 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 on
specific circumstances, such as the type and cost of your usual source of
energy. 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 heating
systems work, how they’re used, their benefits, and how to purchase one
yourself. Please note, however, that this booklet isn’t a technical guide
to designing and installing a system. For that, you’ll need to consult an
experienced solar heating contractor; see “Getting help” in this booklet
for more information.
A solar heating system is a substantial but rewarding investment. It can
reduce 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.
                                                                                  Gen-Con, Inc./PIX09320

What is solar heating?                  have an unshaded area that faces
                                        south, southeast, or southwest,
Solar heaters, or solar thermal
                                        such as a roof. In some cases, a solar
systems, provide environmentally
                                        professional may recommend west-
friendly heat for household water,
                                        facing roofs for solar collectors.
space heating, and swimming pools.
The systems collect the sun’s energy    The type of system you choose,
to heat air or a fluid. The air or      including the type of collector
fluid then transfers solar heat         and whether it is active or passive,
directly or indirectly to your home,    depends on several factors. These
water, or pool.                         include your site, the climate you
                                        live in, installation considerations,
Solar water heaters, sometimes
                                        cost, and how you would like your
called solar domestic hot-water
                                        solar heating system to be used.
systems, may be a good investment
for you and your family. Solar water
                                        What are the basic
heaters are cost effective for many
applications over the life of the       components of a solar
system. Although solar water            thermal system?
heaters cost more initially than        Solar water heaters and solar space
conventional water heaters, the fuel    heaters are made up of solar collec-
they use—sunshine—is free. Solar        tors, and all systems except pool
heating technologies can be used        heaters have some kind of storage.
in any climate. To take advantage       In pool systems, the swimming pool
of solar energy, you usually need to    itself is the storage, and the pool’s
                                        filtration pump circulates the pool
                                        water through the collectors.
                                        Active systems also have circulating
                                        pumps and controls; passive sys-
                                        tems work without this added
     Roof-top collector                 equipment.
                   Solar-heated         Three types of solar collectors are
                      tap water
                                        used for residential applications:
                                        flat-plate, integral collector-storage
               Solar storage tank/      (ICS), and evacuated-tube collectors.
       conventional backup heater
                                        Flat-plate collectors like the one
    Swimming pools and your home
                                        shown on page 3 are the most
  may also be heated using solar energy common type. Glazed flat-plate
                                        collectors essentially are insulated,
   Simplified representation            weatherproofed boxes that contain
of a solar water-heating system a dark absorber plate under one
                                        or more glass or plastic (polymer)
          Glazing                            Flow tubes
          frame                                                         Outlet

      Inlet connection

                    Absorber plate

                           Glazed flat-plate collector

covers. Unglazed flat-plate collec-      coating that absorbs solar energy
tors are simply a dark absorber          well, but which inhibits radiative
plate, made of metal or polymer,         heat loss. Air is removed, or evacuat-
without a cover or enclosure.            ed, from the space between the glass
Unglazed flat-plate collectors made      tubes and the metal tubes to form a
from polymer materials are typically     vacuum, which eliminates conduc-
used in solar pool-heating systems.      tive and convective heat loss. In the
See the photos on pages 1 and 7          United States, evacuated-tube col-
and the diagram on page 9 for            lector systems are used most fre-
examples.                                quently in commercial applications.
Integral collector-storage systems,      Most solar water heaters require
also known as ICS or “batch” sys-        a well-insulated storage tank.
tems, are made of one or more            Solar storage tanks have an addi-
black tanks or tubes in an insulated,    tional outlet and inlet connected
glazed box. Cold water first passes      to and from the collector. Active
through the solar collector, which       solar systems usually include a
preheats the water, and then con-        storage tank along with a conven-
tinues to the conventional backup        tional water heater. In two-tank
water heater. ICS systems are sim-       systems, the solar water heater
ple, reliable solar water heaters.       preheats water before it enters the
However, they should be installed        conventional water heater. In a one-
only in mild-freeze climates because     tank system, like the one shown
the outdoor pipes could freeze in        on page 4, the backup heater is
severely cold weather.                   combined with the solar storage
                                         in one tank.
Evacuated-tube solar collectors
are usually made of parallel rows of     Active solar water heaters use
transparent glass tubes. Each tube       pumps to circulate water or a non-
contains a glass outer tube and          freezing heat-transfer fluid from
metal absorber tube attached to          storage tanks through the collec-
a fin. The fin is covered with a         tors. Active systems are usually
                                          Air vent          Collector

                          Cold water in     Collector
                         P/T relief
               Drain       valve


    Hot water out                                              Air
                        Element                            eliminator   Pump
                                      Pressure               Expansion tank
                          Tank         gauge

                         Active indirect one-tank system

more expensive than passive                    should not be used in climates
systems, but they are also usually             where temperatures often go below
more efficient.                                freezing. Passive systems are typical-
                                               ly less expensive to purchase and
Direct circulation systems use a               maintain than other types of solar
pump to circulate household water              systems. They are also inherently
through the collectors and into the            more reliable and may last longer.
home; they work well in climates               However, passive systems are not
where it rarely freezes. Indirect              usually as efficient as active systems.
circulation systems use pumps
to circulate a non-freezing heat-              ICS passive solar systems may
transfer fluid through the collectors          be best in areas where temperatures
and a heat exchanger. This heats               rarely go below freezing. They are
water that then flows into the                 also good in households with
home. Indirect systems are popular             significant daytime and evening
in climates prone to freezing                  hot-water needs.
                                               Thermosyphon systems work
Passive direct solar water                     because water flows through the
heaters, like the one shown on                 system when warm water rises as
page 5, move household water or                cooler water sinks. In this system,
a heat-transfer fluid through the              the collector must be installed
system without using pumps or                  below the storage tank so that
electricity. Passive systems work              warm water will rise into the tank.
during power outages, but they                 These systems are reliable, but

contractors must pay careful atten-         directory of certified systems on
tion to roof design because the             its Web site along with system
water in the storage tank is heavy.         performance ratings. FSEC publishes
Thermosyphon passive solar sys-             similar information specific to
tems are usually less expensive than        Florida that is useful in other states
active systems, but more expensive          with similar climates. See the
than ICS systems.                           “Getting help” section for contact
How have solar systems
                                            The appearance of the systems has
                                            also improved. Today’s collectors
Since the early 1970s, the efficiency       can usually be mounted flush with
and reliability of solar heating sys-       the roof for a streamlined system
tems and collectors have increased          that looks like skylights. Unglazed
greatly and costs have dropped.             polymer collectors for solar pool
Improvements to materials, a rating         heating are now available in terra
system for consumers, and more              cotta colors as well as black, so
attractive designs have all helped          homeowners can choose the color
to make systems more successful.            that will best match their home.
Low-iron, tempered
glass is now used                                                          Freeze
                                         ICS Collector
instead of convention-                                                     prevention
al glass for glazing.                                                      valve
Improved insulation                                                    From
and durable selective                                                  collector
coatings for absorbers
have improved effi-
ciency and helped to                         To collector
reduce life-cycle costs.
The Solar Rating                                relief valve            Drain valve
and Certification                  valve      Drain valve              Check valve
Corporation (SRCC)                                                     Isolation valve
and the Florida Solar       Cold water in
Energy Center (FSEC)                        Three-way                      Pressure/
certify and rate solar                       ball valve                    temperature
                                                                           relief valve
thermal systems and
equipment. SRCC
                            Hot water out
evaluates product
reliability and rates                        Top element
the performance of
solar water-heating                     Bottom element
systems by subjecting             Water heater tank                       Dip tube
them to technical                                              Drain
reviews. SRCC has a

                                         Passive direct system

Investing in Solar Thermal Technologies
Why should I invest in a                conscious, responsible decision to
solar thermal system?                   help reduce harmful emissions from
                                        fossil fuels, while maintaining your
The first question many people ask      quality of life.
when considering a home expense
is, “How much will it cost?” The        How much will your solar
answer depends on the type of sys-
                                        heating system help the
tem, how you want to use it (water
or pool heating, for example), and      environment?
your geographic location. But most      Depending on the type of conven-
solar thermal systems cost between      tional fuel used, replacing an elec-
$2,000 and $4,500. Although this        tric water heater with a solar heater
is usually more than the cost of a      can offset the equivalent of 40% to
conventional gas or electric system,    100% of the carbon dioxide emis-
today’s solar heating systems are       sions of a modern passenger car.
cost competitive when you consider
your total energy costs over the        Carbon dioxide traps heat in our
entire life of the system.              atmosphere, contributing to the
                                        greenhouse effect, which alters
Your monthly gas or electricity bills   our planet’s climate and ecological
will usually be lower and more          systems. Using solar energy in place
predictable for as long as you own      of nonrenewable fuels may also
the house. Also, solar heating sys-     reduce nitrous oxides and sulfur
tems will insulate you from rising      dioxides, which are components
fossil fuel costs and protect you       of smog.
from fuel-price inflation over time.
Investing in a solar thermal system     Is my home a good place for
could also increase the resale value    a solar heating system?
of your home. Often, the entire
initial cost of the system can be       The first consideration when build-
recovered when you sell your            ing a solar thermal system is the
property. In addition, you will         site. If your site has unshaded areas
be earning an annual 6% to 25%          and generally faces south, it is a
tax-free rate-of-return on your         good candidate for a solar thermal
investment, depending on how            system. A professional installer can
much hot water you use and how          evaluate your roof as a location for
much energy you save.                   collectors. If your roof doesn’t have
                                        enough space, you can also install
Another important reason to invest      the system on the ground. Please
in solar systems may be less tangi-     refer to the system-sizing section of
ble. When you purchase a solar          this booklet for more information
heating system, you support tech-       on space requirements. The amount
nologies that are good for the          of sun that your site receives,
environment. You are making a           how often temperatures dip below
freezing, and other factors will        How big should my solar
also affect the type of solar heating   thermal system be, and which
system you choose.                      features should I look for?
Before getting under way, you need      Some of the answers to questions
to consider your homeowners             about system size and features
association rules and neighbor-         depend on how you plan to use
hood bylaws, also known as codes,       the solar system. Here, you’ll find
covenants, and restrictions (CC&Rs).    general information on sizing
In Arizona, California, and Florida,    systems for water heating, swim-
state laws prohibit CC&Rs that          ming pools, and space heating.
restrict solar system installations.    To locate more specific information,
Nine other states have similar laws     please see “Getting help” on
barring regulations that unreason-      page 17.
ably limit solar energy use in
planned communities. Some cities        Sizing a solar thermal system
and counties have ordinances or         for heating domestic water
require permits for home improve-       Just as conventional water heaters
ment construction, including solar      come in different sizes, so do solar
system installation.                    water heaters. Sizing your solar


           Solar pool heaters are efficient and economical
water heater involves determining        Sizing a solar thermal system
the total collector area and storage     for heating swimming pools
volume you need to meet 90% to           Heating your swimming pool with
100% of your household's hot water       solar energy requires a collector
needs during the summer. Solar-          that is 50% to 100% of the surface
equipment experts use worksheets         area of your pool. Your geographic
and computer programs to help            location and other factors deter-
determine system requirements            mine the exact size.
and collector sizing.
                                         For example, a 15-by-30 foot
Contractors usually follow a             swimming pool in Florida typically
guideline of about 20 square feet        requires a collector that equals
(2 square meters) of collector area      100% of the pool’s square footage,
for each of the first two family         which translates to 450 square feet
members. For every additional per-       of unglazed flat-plate collectors.
son, add 8 square feet (0.7 square       This is because many Florida swim-
meters) if you live in the Sun Belt      ming pool owners use their pools
area of the United States, or 12 to      year round. In contrast, in northern
14 square feet (1.1 to 1.3 square        California, most pools are used only
meters) if you live in the northern      6 to 8 months per year, so systems
United States.                           are typically sized at 60% to 70%
For active systems, the size of the      of the pool’s surface area.
solar storage tank increases with        In general, adding more square
the size of the collector—typically      footage lengthens the swimming
1.5 gallons per square foot of collec-   season and allows owners to use the
tor. A small, 66-gallon system is        pool in colder weather. A pool cover
usually big enough for one to three      or blanket reduces heat loss and
people; a medium-size, 80-gallon         helps maintain warm temperatures
system works well for a three- or        for a longer period.
four-person household; and a large,
120-gallon system is appropriate         Sizing a solar thermal system
for four to six people.                  for space heating
In recent years, homebuilders have       In contrast to solar water heating,
begun including solar water heating      solar space heating usually requires
systems as standard features in          a larger, more complicated system.
some subdivisions. The systems are       Space-heating systems have to store
the same size for every home, and        heat for use when solar energy is
they all work equally well. However,     least available and your house is
large families with greater hot-water    coldest—at night and during the
demand find that a smaller percent-      winter months. Solar space-heating
age of their hot water is provided by    systems are usually combined with
the solar energy system.                 water heating, and they are sized
                                         to accommodate both uses.

   A Check valve
                                                Vacuum breaker/auto-air relief
   B Gate valve
   C Chlorinator
     (if applicable)
   D Drain valve
   E Bypass valve
   F Booster pump                                                                Sensor
     (if necessary)

                                       control box

                                                             D           Gate
                    Pump                        A                        valve

                                                    B                F

                           Fossil fuel heater           C
                           (if applicable)
     Pool water in                                          Warm water
                                                            returns to pool

                            Solar pool-heating system

The amount of solar collector area                      the size and type of your system.
needed to heat your home depends                        Other factors can include the
on many factors. These include the                      climate, the contractor, and the
available solar energy, collector effi-                 system rating. Your state may offer
ciency, local climate, and heating                      solar rebates or other incentives
requirements. Heating requirements                      that will reduce costs.
are based on insulation levels, the
house’s airtightness, and the life-                     Savings and costs for solar
style of the residents. Generally, the                  domestic water heating
area of solar collector is about equal                  Solar heating systems can save
to 10% to 30% of the floor area of                      you money in the long run. FSEC
the house.                                              studied the potential savings to
                                                        Florida homeowners who use
How much money will my                                  common water-heating systems,
solar thermal system save,                              including solar, in comparison
and how much will it cost?                              to electric water heaters. FSEC
                                                        undertook this study because the
Your savings depend on how your
                                                        initial installed cost of a solar water
solar system will be used, as well as
heater is higher than that of a gas     25% of its home energy costs on
or electric water heater. FSEC want-    heating water.
ed to explore costs and savings over
time, beyond the initial installation   If you are building a new home
period. The study found that solar      or refinancing because of a major
water heaters offered the greatest      renovation, the economics are even
potential savings. Annual utility       more attractive. Including the price
costs for solar water heaters were      of a solar water heater in a new
50% to 85% lower than those for         30-year mortgage usually amounts
electric water heaters.                 to between $13 and $20 per month.
                                        The federal income tax deduction
The cost and benefit of purchasing      for mortgage interest attributable
a solar water heater vary from          to the solar system reduces that
region to region, so check costs in     by about $3 to $5 per month. So,
your area. Depending on the price       if your fuel savings are more than
of the conventional fuel, a solar       $15 per month, the solar invest-
water heater can be more economi-       ment is profitable immediately.
cal over the life of the system than    On a monthly basis, you are saving
heating water with electricity, fuel    more than you are paying.
oil, propane, or even natural gas.
That’s because the fuel—sunshine—       Savings and cost for solar
is free.                                swimming pool heating
                                        A solar heating system for your
However, at historically low prices
                                        pool usually costs between $3,000
for natural gas, the total cost of
                                        and $4,000 to buy and install. This
owning a solar water heater with
                                        provides a payback of between
a backup natural gas heater may
                                        1.5 and 7 years, depending on the
be more expensive than owning
                                        cost of the fossil fuel your system
a natural gas heater alone.
                                        replaces. The actual cost and pay-
Nevertheless, as natural gas
                                        back depends on your site, the type
becomes more costly and its avail-
                                        of system you choose, financing,
ability more volatile, solar water
                                        and the length of the pool season.
heaters become more economical.
Solar water heaters are often quite     Often, a payback cannot even be
cost-competitive in new homes.          calculated, because many people
                                        choose not to heat their pool at all,
In many places in the United
                                        given the extra $300 to $600 on
States, homebuilders choose
                                        their energy bill. A solar system
electric water heaters because they
                                        allows these people to swim in a
are easy to install and relatively
                                        pool that was previously too costly
inexpensive. Research shows that
                                        to heat and too cold to use.
the average household with an
electric water heater spends about

Savings and cost for solar               One common way to finance a solar
space heating                            system is through your mortgage or
The cost of a solar space-heating        through a home-equity loan secured
system depends on many factors,          by your home. Mortgage loans
including the size of your house,        offer lower interest rates and longer
how airtight it is, how much of          pay schedules than conventional
your heat will be supplied with a        bank loans, and interest on your
conventional backup, the system          mortgage loan is tax-deductible.
you choose, and your site. In            Financing your system when you
general, solar space-heating systems     apply for your mortgage—whether
can provide 40% to 60% of your           because you are building or refi-
space-heating needs. These systems       nancing—can make the application
are most economical for consumers        process simpler and less costly.
who would otherwise be heating           Conventional bank loans are
with electricity, rather than with       another way to finance your solar
natural gas or other fuels.              system. However, your system is a
But solar space heating is needed        long-term investment; this should
most when sunlight is least              be reflected in the pay schedule for
available, during the winter and         the loan. Look for longer terms and
at night—and needed least when           lower interest rates, which will help
sunlight is most available, during       keep your solar thermal system
the summer and the daytime. So           affordable.
today’s solar technologies are not
likely to be a cost-effective solution
for active solar space heating in        Many states have incentives for
most homes. However, a good alter-       buying solar technologies. Check
native is to simply to use passive       with your state or local energy
solar building techniques. See the       office or your state departments
EERE Web site,,       of revenue or finance for informa-
for more information.                    tion. Some electric utilities offer
                                         rebates to customers who install
How can I finance the cost               solar energy equipment because
of my solar thermal system?              these installations help utilities
Are there incentives?                    reduce energy use during times
                                         of high demand.
                                         You can also check the National
Financing the cost of your solar         Database of State Incentives for
thermal system is not as tricky          Renewable Energy (DSIRE). DSIRE
as it may seem. Although some            is prepared by the North Carolina
special programs are available to        Solar Center. It provides informa-
help you purchase solar thermal          tion on financial and regulatory
technologies, most of the financing      incentives to promote renewable
options are familiar ones.               energy technologies. For informa-
                                         tion, see “Getting help” on page 17.

What are the maintenance               may need to be cleaned in dry
issues and repair costs for            climates where rainwater does
a solar thermal system?                not provide a natural rinse.

The costs of maintaining your solar    Regular maintenance on simple
thermal system depend on the type      systems can be as infrequent as
of technology you choose and how       every 3 to 5 years, preferably by
often temperatures in your area fall   a solar contractor. Systems with
below freezing. Properly maintaining   electrical components usually
your system will keep it running       require a replacement part or two
smoothly.                              after 10 years. Simple, regular sys-
Passive systems do not require         tem checks can also be effective.
much maintenance. For active           For example, one easy way to
systems, discuss the maintenance       check the system is to carefully
requirements with your system          feel the hot-water pipes going
provider and consult the system        into the storage tank after the
owner’s manual. Plumbing and           system has been working on a
other conventional components          clear, warm day. If the pipes are
require the same maintenance as        hot, your system is working
conventional systems. Glazing          properly.

                                                                              Industrial Solar Technology/PIX12963

Specialists can safely and efficiently install solar thermal systems
Selecting a solar heating contractor
Who sells and installs                Has your company installed
solar thermal systems?                solar thermal systems for solar
                                      water heating, pool heating,
Depending on your area, the           or space heating?
simplest way to find a solar
thermal systems contractor is to      Choose a company that has
look in the yellow pages under        experience installing the type of
“Solar Energy Equipment and           system you want and servicing
Systems—Dealers.” Most of the         the applications you select.
listings will probably be for solar
                                      How many years of experience
water heating, photovoltaic (solar
                                      does your company have with
electric), or electric systems
                                      solar heating installation?
                                      Obviously, the more experience
You can also contact your utility     the better. A business that has
company to get information on         been working with these systems
recommended vendors, or search        for a long time will be more
on the Internet for solar water       professional, know more about
heating, solar pool heating, or       current technologies and recent
solar space heating, depending on     advances, and be less likely to
the application you are interested    make costly mistakes. Request a
in installing.                        list of past customers who can
Your state may have an active         provide references.
chapter of the Solar Energy
                                      Is your company licensed?
Industries Association (SEIA), a
trade association of contractors,     Having a valid plumber’s or solar
distributors, and manufacturers.      contractor’s license is required in
See “Getting help” for contact        some states for solar thermal
information.                          system installation. You can
                                      confirm licensing by contacting
How do I choose among                 your state contractor licensing
solar thermal system                  board. Local requirements may
                                      also include a local contractor’s
                                      license. Call your city and county
One way to choose a contractor        for information on other required
is to check your list of potential    licenses.
companies for the ones nearest
you. Ask them what products and       For you to obtain certain rebates,
services they offer. Here are a few   your contractor may have to
questions you might want to ask       demonstrate special knowledge
potential vendors.

about solar installations through       One solution is to ask for bids
one or more of the following:           on systems certified by the
                                        Solar Rating and Certification
 • Possession of a solar contractor     Corporation (SRCC). If possible,
   specialty license issued by a        have each bid specify system type
   local building jurisdiction          and size, energy output, mainte-
 • Certification in solar thermal       nance requirements, and cost.
   systems by a group such as the       Cost should include having the
   state chapter of SEIA                system installed and getting it
                                        up and running, as well as the
 • A letter from the solar heating      cost of hardware, permits, sales
   manufacturer that indicates          tax, and warranties.
   that the installer has the neces-
   sary experience and training to      A system warranty is crucial in
   install solar systems.               comparing bids. A solar rebate
                                        program may require a written
Does your company have any              installation warranty, for example
pending or active judgments             a 2-year parts-and-labor warranty
or liens against it?                    in addition to manufacturers’
As with any project that requires       warranties on system components.
a contractor, due diligence is          The company may offer other,
recommended. Your state contractor      longer warranties, particularly
licensing board can tell you about      on the collectors. However, solar
any complaints against state-           systems are more than collectors;
licensed contractors. The Better        active systems include electronic
Business Bureau is another good         components, pumps, valves, and
source for such information.            wiring. Make sure you know what
                                        your warranty covers and that
How do I choose among bids?             the company stands behind the
Is the least expensive the              full warranty.
best deal?                              If you have several bids, you may
It is usually a good idea to get more   wonder if the lowest bid is the
than one bid for installation of your   best deal. Sometimes it is not. A
solar system. Make sure that all the    solar thermal system installer is
bids you receive are based on the       in business to make money; over-
same information and require-           head and operating expenses must
ments. For example, comparing a         be covered. A low price could be
bid for a system mounted on your        a sign of inexperience, or of a
roof with a bid for one mounted         company without staying power.
on the ground would not tell you        Contractors that expect to stay in
how the two bids compare—it             business must charge enough to
would probably tell you more about      cover their products and services
how the two types of installations      plus make a fair profit. Price is
compare.                                not the only consideration.

Before you put solar heating to work
Do I need a conventional               The ICS system stores hot water in
system as a backup?                    addition to collecting solar heat,
                                       and the instantaneous water heater
Whether you need a backup system       provides hot water when solar heat
for your solar thermal system          is not available.
depends largely on the type of
system you choose and where you        Most people do not need or use
live. Solar water-heating systems      a backup heater with solar pool
almost always require a backup         heaters. In freeze-prone climates,
system for cloudy days and times       solar pool heaters are used mainly
of increased demand. This backup       in summer. Spas or hot tubs are
system is typically a conventional     an exception. Spa owners may use
gas or electric water heater and       their solar system to heat both the
may already be part of the solar       pool and the spa, but will use a
system package. It may also be         backup heater to get the spa to a
part of the solar collector, such as   higher temperature. In climates
rooftop tanks with thermosyphon        where it rarely freezes, pool heaters
systems. For example, an integral      may be used year-round.
collector-storage system (ICS)
                                       If you decide to install solar thermal
may be packaged with an instanta-
                                       space heating, you will almost
neous gas water heater for backup.

                                                                                Sun Systems/PIX05978

  Rooftop collectors can be installed on most roofing materials
certainly need a backup system.        the price of obtaining permits and
Space-heating systems require a        inspections is included in the bid
large collector area, significant      and final cost estimate.
storage volume, and a highly
efficient building envelope to         What about insurance?
produce enough energy to heat
                                       If you are buying a solar heating
your home at night and during
                                       system for your home, your regular
the winter. Solar space heating
                                       homeowners insurance should
usually provides 40% to 60% of
                                       cover your needs. However, if
your home’s space-heating needs.
                                       insurance coverage becomes an
A backup system ensures that
                                       issue, please refer to “Getting help”
your house is comfortably warm
                                       on page 17.
during power outages, cold snaps,
and extended cloudy periods.
                                       Will I need warranties?
Many building codes and mortgage
lenders require a conventional         Warranties are an important factor
backup space heater.                   in the bidding process and an
                                       important aspect of the system
Will I need any permits                you choose. Make sure you know
or inspections?                        the warranties that your system
                                       manufacturer and installer offer
If you live in a community with        for your equipment and hardware,
a homeowners association, check        as well as parts-and-labor war-
to see if any approvals, permits,      ranties. Check to make sure the
or inspections are required. Always    manufacturer can provide support
obtain the necessary approvals         and supplies if the installer is
from the association before begin-     not available.
ning construction. Homeowners
associations, towns, cities, and       You can usually obtain a full-system
counties usually have a legal right    warranty plus parts-and-labor for
to require approval before building.   at least 1 to 3 years. This means
However, some states have solar-       you will not be responsible for
rights laws that may apply if          system problems covered by the
approval is denied.                    warranty in the first year or two
                                       of system operation.
You will probably need to obtain
permits from the building depart-      Will I need a maintenance
ment that has jurisdiction in your
state, county, or city. Plumbing,
building, and electrical permits may   A maintenance agreement may
be required. These permits typically   be part of your warranty. Have
require a final inspection after the   the contractor prepare a schedule
system has been installed. Check       of required or recommended
with your solar heating system         maintenance before you purchase
contractor to find out whether         your system.

Getting Help
American Solar Energy Society (ASES)   Solar Benefits Model Software
2400 Central Avenue, Suite G-1
Boulder, CO 80301                      solarbuildings/sbm.html
Phone: (303) 443-3130                  Solar Energy Industries
Fax: (303) 443-3212                    Association (SEIA)
E-mail:                  1616 H Street NW, 8th Floor
                                       Washington, DC 20006-4999
Database of State Incentives 
for Renewable Energy (DSIRE)           Phone: (202) 628-7745                       Fax: (202) 628-7999
Florida Solar Energy Center (FSEC)     Solar Rating and Certification
Public Affairs Division                Corporation (SRCC)                       c/o FSEC
Phone: (321) 638-1015                  1679 Clearlake Road
Fax: (321) 638-1010                    Cocoa, FL 32922-5703
                                       (See standards document OG-300)
National Renewable Energy Laboratory   Phone: (321) 638-1537
Solar Energy Technology Program        Fax: (321) 638-1010         E-mail:

                                                                            Craig Christensen, NREL/PIX12943

     Solar thermal technologies work in a variety of climates
About the Office of Energy Efficiency and Renewable Energy
A Strong Energy Portfolio for a Strong America
Energy efficiency and clean, renewable energy will mean a stronger economy, a
cleaner environment, and greater energy independence for America. By investing in
technology breakthroughs today, our nation can look forward to a more resilient
economy 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 Energy
invests in a portfolio of energy technologies that will:

 • Conserve energy in the residential, commercial, industrial, government, and
    transportation 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 needs
Building Technologies Program—Homes, schools, and businesses that use less
energy, cost less to operate, and, ultimately, generate as much power as they use
Distributed Energy & Electric Reliability Program—A more reliable energy
infrastructure and reduced need for new power plants
Federal Energy Management Program—Leading by example, saving energy
and taxpayer dollars in federal facilities
FreedomCAR & Vehicle Technologies Program—Less dependence on foreign
oil, and eventual transition to an emissions-free, petroleum-free vehicle
Geothermal Technologies Program—Tapping the Earth's energy to meet
our heat and power needs
Hydrogen, Fuel Cells & Infrastructure Technologies Program—Paving the
way toward a hydrogen economy and net-zero carbon energy future
Industrial Technologies Program—Boosting the productivity and competitiveness
of U.S. industry through improvements in energy and environmental performance
Solar 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's
best energy-efficient and renewable technologies in homes, communities, and businesses
Wind & Hydropower Technologies Program—Harnessing America's abundant
natural resources for clean power generation

To learn more, visit

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

U.S. Department of Energy
Office of Energy Efficiency and Renewable Energy
1000 Independence Avenue, S.W.
Washington, D.C. 20585

December 2003 • DOE/GO-102003-1824