If you have an electric water heater, install a timer that allows you to turn the unit off at night when not in use—you'll save an additional 5 – 12% on energy needed to heat the water. In addition, some utility companies may offer incentives for customers who permit control devices to be installed that shut off water heaters during the utility company's peak demand hours.

Install heat traps, one-way valves or loops of pipe, which prevent heated water in a storage tank from mixing with cooled water in pipes. Most new water heater models have factory-installed heat traps. Heat traps can save you $15 – 30 per year by preventing convective heat losses through the inlet and outlet pipes.

If you have a tank-style water heater, drain about a quart of water from the water tank every 3 – 6 months. This helps to remove sediment that slows down heat transfer and lowers the efficiency of your water heater. Follow the manufacturer's recommendations for your specific unit.

If your water heater is more than 10 years old, it's a good idea to start shopping for a new one now. This will give you a chance to do some research and select the type and model that most appropriately meets your needs. Although most water heaters last 10-15 years, it might be economically smarter to replace your water heater early; the lower utility bills could be worth it. Compare costs: purchase price and lifetime maintenance and operation costs.

For safety concerns as well as energy efficiency reasons, when buying fuel-fired water heaters, look for units with sealed combustion or power venting to avoid back drafting of combustion gases into your home. If fuel-fired water heaters are located in interior spaces, such as interior mechanical rooms connected to conditioned spaces or laundry rooms, they should include provisions for outside combustion air. Also, install a hardwired carbon monoxide alarm (with battery back up) nearby.

Install an ENERGY STAR® clothes washer. Most of the energy consumed when washing clothes is used to heat the water.

Install an ENERGY STAR® dishwasher; as with clothes washers, most of the energy consumed by dishwashers is used to heat the water.

If you don't use a dishwasher (which is designed to clean best with water at 140°F), or if you have a dishwasher with a preheating element, setting the main water heater at 120°F is fine for most households. Note: most electric water heaters have two thermostats (one for each heating element), and it’s important to make sure they're both at the same setting. For each 10°F reduction in water temperature, you can save 3 – 5% in energy costs.

Source: UF/IFAS Energy Efficient Homes: Water Heaters; Wendell A. Porter, Hyun-Jeong Lee, and Kathleen C. Ruppert, 2008.

Additional Resources

UF IFAS Energy Efficient Homes: Water Heaters- http://edis.ifas.ufl.edu/FY1025

 American Council for an Energy-Efficient Economy. Water Heating and Emerging T echnologies Report, February 2007 http://www.aceee.org/emertech/2006_AdvGasWH.

Energy Star. Energy Star Program Eligibility Criteria for Residential Water Heaters, April 1, 2008, http://www.energystar.gov/ia/partners/prod_development/new_specs/downloads/water_heaters/WaterHeater_ProgramRequirements_2008.pdf