Five Ways to Slash Water Heater Energy Use

America may be the only country in the world that heats
household water 24/7. Typically the second largest household energy use, heating water consumes 13 to 17 percent of the average residential energy bill. It’s an unnecessary expense easily remedied.

First, if a unit is older than 10 years, it’s likely running at less than 50 percent efficiency. Updating the appliance will yield significant energy savings. Depending on local utilities, climate and family use, recommendations range from a new tank, perhaps paired with a heat pump or exchange, to new tankless and solar technologies.
Eligible brands of the latter two can earn 2007 tax credits if installed by December 31. Tip: tankless units work best with natural gas.

Second, it’s important to "right size" a unit for household needs. Tanks range from 30 to 80 gallons, and a 40-gallon tank generally serves the average home. Tankless, which heat water only as it’s needed, come in four sizes (e.g. RheemTankless.com). Look for a high energy factor for efficiency and a first-hour rating suited to the family’s heaviest period of use. Note that Energy Star does not currently rate water heaters.

Third, wrap the holding tank and exposed hot water pipes in an insulating jacket. Buy inexpensive insulation from a home improvement store or find space-age tank wrap at RadiantBarrier.com. This alone can cut
heat loss 25 to 40 percent, saving 4 to 9 percent on the utility bill.

Fourth, try lowering the water temperature. Most families do well at 120º F (midway between low and
high settings). Each 10º drop will save 3 to 5 percent in heating costs.

Fifth, any basic tank needs a multi-on-off timer. A couple we know has cut heating time to just 3-½ hours a day. Water heats in 15 to 30 minutes and holds for hours, ready for use.

For more information visit ACEEE.org/consumerguide/waterheating.htm. For tax and rebate incentives see DSIREUSA.org and EnergyTaxIncentives.org