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Water Heaters

Water Heaters
Image of Storage Water Heater.
Title "Renewable Energy."
Department of Energy Logo.
Many homeowners wait until their water
heater fails before shopping for a replace-
ment. Because they are in a hurry to regain
their hot water supply, they are often
unable to take the time to shop for the
most energy-efficient unit for their specific
needs. This is unfortunate, because the
cost of purchasing and operating a water
heater can vary greatly, depending on the
type, brand, and model selected and on
the quality of the installation.
To avoid this scenario, you might want to
do some research now—before you are
faced with an emergency purchase. Famil-
iarize yourself today with the options that
will allow you to make an informed deci-
sion when the need to buy a new water
heater arises.
Types of Water Heaters Available Within the last few years, a variety of
water heaters have become available to
consumers. The following types of water
heaters are now on the market: conven-
tional storage, demand, heat pump, tank-
less coil, indirect, and solar. It is also
possible to purchase water heaters that
can be connected to your home’s space-
heating system.
Storage Water Heaters A variety of fuel options are available for
conventional storage water heaters—elec-
tricity, natural gas, oil, and propane. Rang-
ing in size from 20 to 80 gallons (75.7 to
302.8 liters), storage water heaters remain
the most popular type for residential heat-
ing needs in the United
States. A storage heater
operates by releasing hot
water from the top of the
tank when the hot water
tap is turned on. To
replace that hot water,
cold water enters the
bottom of the tank,
ensuring that the tank
is always full.
Selecting a New Water Heater ENERGY
                         AND RENEWABLE
Storage Water Heater Pressure/
relief valve
and gas valve
Hot water outlet Vent pipe
Cold water inlet
Flue tube/
heat exchanger
Flue baffle
Insulation Combustion air
Anode rod Gas burner Storage water heaters remain the most frequently used type
of water heater for residential purposes.
This document was produced for the U.S. Department of Energy (DOE) by the National Renewable Energy Laboratory (NREL), a DOE national laboratory.
The document was produced by the Technical Information Program, under the DOE Office of Energy Efficiency and Renewable Energy. The Energy Efficiency
and Renewable Energy Clearinghouse (EREC) is operated by NCI Information Systems, Inc., for NREL/DOE. The statements contained herein are based on
information known to EREC and NREL at the time of printing. No recommendation or endorsement of any product or service is implied if mentioned by EREC.
  DOE/GO-10095-064            FS 205
January 1995
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