Lower Water Heater Thermostat

One of the quickest, easiest and surest energy saving measures is lowering the thermostat setting on your water heater. Although some manufacturers and installers set water heaters at 140°F, settings between 115° and 120°F work fine for many households. That's about midway between the “low” and “medium” settings on most water heaters. The bottom line is keeping your water heater set at the lowest temperature that provides you with sufficient hot water. You can always try turning it down, then inch it back up if you find you are running out of hot water or having other problems. Moreover, there is a safety benefit to lowering your water heater temperature. Water heated to 140°F water can pose a scalding hazard, especially a concern where young children have access to faucets.

To check the temperature of the water coming out of your faucets is close to your thermostat setting, fill a glass with hot water, and then place a thermometer in the water until the temperature stops rising. If you decide to change the water heater setting and you have a gas unit, simply turn the knob to a lower setting. On gas water heaters, thermostats are usually visible knobs at the bottom of the unit with clearly marked settings of High, Medium, and Low.

If your water heater is electric, turn off the power at the circuit breaker before removing the access panels and making the adjustments. Electric water heaters often have two thermostats -- one for the upper heating element and one for the lower heating element. These should be adjusted to the same level to keep one element from doing all the work and wearing out prematurely.

If you have a dishwasher without a booster heater, you may need to keep the water temperature up to 140°F, the “medium” setting, or buy a new, more efficient, dishwasher with a booster heater. Some think the 140°F water is not required to sanitize dishes; it's not. It would take much hotter water to do that. Instead, 140°F water is necessary to dissolve most dishwasher soaps. Not only will lowering the thermostat save a lot of energy, but it will also increase the life of your water heater and reduce the risk of children scalding themselves with the hot water.

When you plan to be away from home for three or more days, turning the water heater thermostat down to the lowest setting, or even turning the heater off completely, can help you achieve additional savings. On gas units, be prepared to relight the pilot light when you return.

To estimate your potential for savings, for each 10°F reduction in water temperature, water-heating energy consumption can be reduced 3% to 5%.