Unless you are one of the few uberconscientious and conservation-minded hand washers, automatic dishwashers are superior to hand washing with respect to both water and energy savings.

New dishwashers use between five and eight gallons of water, and about 1.6 kilowatt hours of electricity per load.

Kitchen faucets equipped with aerators to reduce the flow of water will dispense about 1.5 gallons of water per minute. If you’re one to leave the faucet running while you wash and rinse, it will take less than six minutes for you to use more water than would be used by your dishwasher to complete an entire cycle.

Washing and rinsing a load of dishes by hand uses an estimated 20 gallons of water. Even if a low-flow faucet could cut this volume in half, the total water down the drain would still exceed the amount used by the dishwasher.

As far as energy is concerned, roughly 80 percent of the energy consumed by an automatic dishwasher is used to heat the water. So, unless you’re hand washing in cold water, it’s unlikely that you’re conserving energy—in fact, you actually might be using more.

If it is necessary to wash certain dishes by hand (or if you live without an automatic dishwasher) you can conserve water by not letting the water run while you rinse the dishes. If you have two sinks, you can fill one with soapy water for washing, and one with clean water for rinsing. Otherwise, you can use a plastic tub on the counter to hold your clean rinse water.

Use the following tips to save additional water and energy:

water. New dishwashers do not require dishes to be rinsed before they’re loaded. dishwasher when the final rinse cycle has ended and let the dishes air dry.—Colleen Howell