In order to activate dishwasher detergents and effectively melt grease from dishes the water temperature should be set at least 140°F for most residential situations.

More Info: Many of today's Energy Star dishwasher models contain a booster heater, which allows you to set your water heater temperature to 120°F.

Handwashing versus Dishwasher

One of the benefits of using a dishwasher is the fact that you can run water hot enough to do a thorough, sterile job, unlike handwashing where you can only run the water to a temperature that is comfortable for the skin.

Energy Star models can save 5,000 gallons of water over handwashing in a single year.  Energy Star models  use between 3-5 gallons of water per load compared to 10-15 gallons for older models. Given the fact that 80% of the energy expended in a dishwasher is used to heat up the water, the savings can be substantial.

Did you know that you can save an average of 230 hours of personal time by using a dishwasher instead of handwashing? That equates to a ten-day Caribbean cruise!

Benefits of Lowering Water Heater Temperature

According to the US Department of Energy, for each 10°F reduction in water heater temperature, you can save 3-5% in energy costs.

Lowering the water temperature will also help your water heater last longer by slowing the mineral buildup and corrosion in the unit and the pipes.