Since You Asked: Calgon, take us away!

I heard somebody say the other day that using a dishwasher is more efficient and better for the environment than washing dishes by hand. How can that possibly be?

— Lynn L., Central Point

The answer might depend on how deeply you care to dig into all the aspects of "efficient" dish washing, Lynn.

Do you want to factor in the total cost of producing the dishwasher, including the metal and plastic? Or just the day-to-day cost of electricity to run the machine and heat the water? What about if you heat your water with natural gas? Or propane delivered by a truck? Eliminate soiled dishes by avoiding eating altogether? Argghhh!

This is one of those questions that keeps some well-intentioned people awake at night. Fortunately, there's no shortage of opinions out there in cyberspace.

The general conclusion seems to be that you use less electricity when you wash by hand (no dishwasher motor to run) but you use more hot water washing by hand. Someone who uses lots of hot water might easily consume more power than the dishwasher motor.

Fortunately a team of researchers in Bonn, Germany, decided to study this issue scientifically in 2005. They concluded that the dishwasher uses only half the energy, one-sixth the water, and less soap to produce dishes that are cleaner than those that are washed by hand. So keep your dishwasher, and enjoy a few minutes of free time.

To get maximum efficiency, follow these tips from an environmental Web site called

  • buy an energy-efficient dishwasher
  • run it with a full load
  • use phosphate-free dishwasher detergent
  • skip the pre-rinse
  • turn down the heat
  • let the clean dishes air dry instead of running the dry cycle
  • use fewer dishes to have fewer dishes to wash
  • install a passive solar water heater.

Send questions to "Since You Asked," Mail Tribune Newsroom, P.O. Box 1108, Medford, OR 97501; by fax to 541-776-4376; or by e-mail to

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