Your biggest opportunity for
savings is to use less hot water. In addition to saving energy (and money),
cutting down on hot water use helps conserve dwindling water supplies, which in
some parts of the country is a critical problem. A family of four, each
showering five minutes a day, can use about 700 gallons per week—a three-year
drinking water supply for one person! Water-conserving showerheads and
faucet aerators can cut hot water use in half. That family of four can save
14,000 gallons of water a year and the energy required to heat it just by
changing the shower head.
Do as much cleaning as
possible with cold water to save the energy used to heat water.
Check your faucets for
leaks. Leaks waste both water and energy!
your existing water heater: Installing an insulating jacket on your existing
water heater is one of the most effective do-it-yourself energy saving
projects, especially if your water heater is in an unheated basement or space.
The insulating jacket will reduce standby heat loss—heat lost through the
walls of the tank—by 25–40%, saving 4–9% on your water heating bills. Water
heater insulation jackets are widely available for around $10. Some newer
water heaters come with fairly high insulation levels, reducing (though not
eliminating) the economic advantages of adding additional insulation. In fact,
some manufacturers recommend against installing insulating jackets on their
energy-efficient models. Always follow directions carefully when installing an
insulation jacket. Leave the thermostat(s) accessible. With conventional gas
and oil fired water heaters, you need to be careful not to restrict the air inlet(s) at the bottom or the draft hood at the top.
pipes: Insulating your hot water pipes will reduce losses as the hot water is
flowing to your faucet and, more importantly, it will reduce standby losses
when the tap is turned off and then back on within an hour or so. A great deal
of energy and water is wasted waiting for the hot water to reach the tap. Even
when pipes are insulated, the water in the pipes will eventually cool, but it
stays warmer much longer than it would if the pipes weren’t insulated.
temperature: Keep your water heater thermostat set at the lowest temperature
that provides you with sufficient hot water. For most households, 120°F water
is fine (about midway between the “low” and “medium” setting). Each 10°F
reduction in water temperature will generally save 3–5% on your water heating
costs. When you are going away on vacation, you can turn the thermostat down
to the lowest possible setting, or turn the water heater off altogether for
additional savings. With a gas water heater, make sure you know how to relight
the pilot if you’re going to turn it off while away.
Some new water heaters have
a "vacation" setting you can use to save energy if you're away for more than a
few days. Turn the thermostat "down" or "off" when you're gone for more than
If your storage water heater
doesn't have heat traps, you can save energy by adding them to your water
heating system. They can save you around $15–$30 on your water heating bill by
preventing convective heat losses through the inlet and outlet pipes.
Heat traps — valves or loops of pipe — allow water to flow into the water heater
tank but prevents unwanted hot-water from flowing out of the tank. The valves have
balls inside that either float or sink into a seat, which stops convection.
These specially designed valves come in pairs. The valves are designed
differently for use in either the hot or cold water line.
A pair of heat traps
costs only around $30. However, unless you can properly solder a pipe joint,
heat traps require professional installation by a qualified plumbing and
heating contractor. Therefore, heat traps are most cost effective if they're
installed at the same time as the water heater. Today, many new storage water
heaters have factory-installed heat traps or have them available as an option.
Any hot water that
goes down the drain carries away energy with it. That's typically 80–90% of
the energy used to heat water in a home. Drain-water (or grey water) heat
recovery systems capture this energy to preheat cold water entering the water
heater or going to other water fixtures.
Heat Recovery - How It Works
Drain-water heat recovery
technology works well with all types of water heaters, especially with
solar water heaters. Also, drain-water heat exchangers can recover heat
from the hot water used in showers, bathtubs, sinks, dishwashers, and clothes
washers. They generally have the ability to store recovered heat for later
use. You'll need a unit with storage capacity for use with a dishwasher or
clothes washer. Without storage capacity, you'll only have useful energy
during the simultaneous flow of cold water and heated drain water, like while