Reducing the costs of water heating
Water heating is the third largest energy expense in
the home. Understanding the costs of water heating and
what you can do to lower those costs is yet another way
homeowners can Take Control and Save.
There are three costs associated with the energy used in
storage-tank water heaters: demand costs—the initial
costs of heating water; the costs associated with standby
losses when a water heater loses heat through the tank
shell; and the costs of distribution losses that occur
when hot water loses heat while running through pipes.
Lowering the tank temperature and using water efficiently
are the easiest ways to lower demand costs. There are
good reasons for setting a water temperature lower than
120 degrees Fahrenheit:
Standby or standing loss refers to the heat lost from a
hot-water storage tank through its shell. The water heater
has to reheat the same water even when no water is being
used. Households using less hot water have a higher
percentage of standby losses, especially if the home’s water
heater is located in an unheated area.
Upgrading to a higher-efficiency water heater is the
quickest and easiest way to reduce standby losses. More
efficiency means a higher initial cost; however, you will
continue to receive the energy savings over the lifetime of
the unit.
Insulating your hot-water pipes will reduce distribution
losses as the hot water flows to your faucet.
1) The system loses heat faster at high temperatures.
2) A higher temperature increases the rate of corrosion
on internal fittings and other surfaces.
Hot water out
to house
3) Important safety note: Hot tap water is a scalding
hazard, especially to children and seniors. Scalding
occurs in two seconds at 150 degrees while it takes
10 minutes in water heated to 120 degrees.
Cold-water line
Usage is determined by how many live in your home.
No two families’ hot-water use is exactly alike; keep in
mind your family’s lifestyle and habits and try to use hot
water as efficiently as possible.
Clothes washer
Tub bath
Shower bath
Typical hot water usage
25 to 40 gallons per load
5 to 10 gallons per load
15 to 25 gallons
3 gallons per minute
Hand washing
1 to 2 gallons
Food preparation
3 to 6 gallons
Add pipe insulation to as much of the hot-water lines as can be
reached, along with about three feet of the water line leading
into the water heater.
Pipe insulation comes in different forms: closed-cell flexible
foam tubes (R-3 to R-5); rigid foam (R-7); and fiberglass
batts (R-2 to R-3). Use a good-quality plastic or rubber foam
at least 3-4 inches thick. Do not cover unions or fittings at
the ends of flexlines (these areas need to be clearly visible),
and stay clear of the draft diverter on gas heaters.
© 2008 Associated Electric Cooperative Inc. All rights reserved.
Insulating older water heaters
An older water heater installed in an unheated area may need some extra insulation to reduce the amount of standby loss.
Lightly place your hand against the side of the water heater; if it’s warm, you may want to add insulation by purchasing
and installing a water-heater blanket.
Insulation blankets with an insulation value of at least R-11 can be found in hardware and home
stores at a minimal cost. Make sure you buy an insulation blanket designed for your type of waterheating system (insulation blankets are NOT recommended on oil-fired water heaters.)
Extreme care must be taken to ensure water-heater blankets are installed correctly.* Blankets
come with many problems, including restricted access to the water heater and the potential for
hiding leaks, accelerating rust damage, restricting combustion air, causing electric components
to overheat and obstructing venting.
If safety stickers are hidden under a blanket, the homeowner may be liable if someone is burned
or scalded. Thoroughly read the instructions supplied with the blanket/wrap before installing
the product.
Make sure all fittings are dry and in good shape before installing the wrap. Put a Gas Appliance
Manufacturers Association safety sticker (available from GAMA or a plumber) on the blanket.
Leave the anode, relief valve and controls exposed for routine maintenance. With gas heaters, take
special precautions not to block the air intake opening and to keep the insulation from touching the
flue. This is essential for the heater to function properly and to avoid a fire hazard.
Adding a blanket to water heater models purchased within the last five years is not recommended. Installing an insulating
blanket does not void the water heater tank warranty; however, homeowners should check installation and safety
recommendations in the manual that came with the unit. Other warranty and installation information is available from
these manufacturers:
American Water Heater Co.
www.americanwaterheater.com • 800-999-9515
www.reliancewaterheaters.com • 800-365-4054
A.O. Smith
www.hotwater.com • 800-527-1953
www.rheem.com • 800-432-8373
www.bockwaterheaters.com • 888-784-8322
www.richmondwaterheaters.com • 334-260-1400
Bradford White
www.bradfordwhite.com • 800-334-3393
http://waterheating.ruud.com • 800-621-5622
General Electric
www.geappliances.com/products/water • 800-626-2005
State Industries
www.statewaterheaters.com • 800-365-8170
www.kenmore.com • 888-536-6673
www.vaughncorp.com • 800-282-8446
www.marathonheaters.com • 800-321-6718
*AECI and its member cooperatives make no claims to the recommendation and safety of water-heater blanket installations. Consumers should thoroughly read blanket manufacturers’ instructions and recommendations of
the use of this product.
© 2008 Associated Electric Cooperative Inc. All rights reserved.
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