The biggest cost of washing dishes and clothes comes from the energy required to heat the water. You’ll significantly reduce energy costs if you purchase and use energy-efficient machines.

Dishwashers

Conventional wisdom says that washing dishes by hand saves hot water. If, however, you wash dishes several times a day, this can be more expensive than operating an energy-efficient dishwasher when properly used and when operated with full loads.

One feature that makes a dishwasher more energy efficient is a booster heater. This device increases the temperature of the water entering the dishwasher to 140ºF. Some dishwashers have built-in boosters, while others require manual selection before the wash cycle begins. Some also only activate the booster during the heavy-duty cycle. Dishwashers with booster heaters typically cost more, but pay for themselves with energy savings in about 1 year if you also lower the water temperature on your water heater.

Consumer Guide to Home Energy Savings (Ninth Edition)

Dishwashers come in smaller capacities. These may appear to be more energy efficient on the Energy Guide Label, but reduced capacity may force you to operate the machine more frequently, and your energy costs could be higher. It depends on the size of your household.

Another dishwasher feature that reduces hot water use is the availability of cycle length selections. Shorter cycles require less water.

Clothes Washers

Unlike dishwashers, clothes washers don’t require a minimum temperature for optimum cleaning. Use either cold or warm water for most laundry loads. Cold water is always sufficient for rinsing.

Inefficient clothes washers can cost three times as much to operate than energy-efficient ones. Select a new machine that allows you to adjust water level and temperature for different loads. Efficient washers spin-dry your clothes more effectively too, saving energy when drying. Also, front-loading machines use less water and energy than top loaders.

Clothes washers come in smaller capacities. These may appear to be more energy efficient on the Energy Guide Label, but reduced capacity may force you to operate the machine more frequently, and your energy costs could be higher. It depends on the size of your household.