We don't have a dishwasher at my house, a lapse my unfortunate dinner guests complain about bitterly when they are kind enough to take a turn at the sink. "Haven't you read that dishwashers use less hot water than washing by hand?" they ask hopefully.
Well, you know, I have read that. A 1988 Ohio State University study showed that the average automatic dishwasher uses 9.9 gallons of water compared with 15.7 gallons used by the average hand dish washer.
Of course, the study didn't count the 15.7 gallons the average person loading the dishwasher uses to rinse the dishes clean before putting them in the machine. And the study assumed that the average hand dish washer leaves the warm water running throughout.
Cynthia Putnam, of the Washington State Energy Office's Energy Extension Service, has done some informal research on the subject. She finds that individual styles vary so widely that it may be impossible to generalize about which method uses more hot water. (In her own home, she ponds the water in two sinks and uses less than six gallons.)
Why does Putnam care? When you use hot water, you consume both fresh clean water, a dwindling, not-so-renewable, natural resource, and the energy required to heat it. The less hot water we millions use washing our millions of dishes every day, the more energy and water we can save.
Washing dishes is no one's favorite activity, no matter how the job is accomplished. If you have a dishwasher, and you find it convenient, use it. You prefer to wash by hand? Go right ahead. If you are interested in conservation, though, there is probably some room for improvement, whatever your style. Here are some ideas, automatic dishwashers first:
* Don't pre-rinse dishes. Scraping them thoroughly should be enough. If the dishes will sit for hours or days, keep a pond of cold water in the sink and give each dish a dip and a rub before loading.
* Run only full loads. This may be impractical if you live alone and don't use a lot of dishes at one time. Consider hand washing.
* Use the "air dry" setting, or shut off the machine before the drying cycle kicks in and prop open the door to let the dishes dry.
* Always use the shortest cycle on the machine.
Dishwashers require water heated to 140 degrees Fahrenheit to do a decent job. If you have an older machine, you need to keep your house's water heater set that high -- much higher than you need for other household activities. Water that hot wastes energy and can scald children badly. New models come with an internal heat booster, allowing you to leave your hot water heater at a safe and efficient 120 degrees. If you have an older model with no booster, consider replacing it. You can buy one secondhand, if a new one is too pricey.
Washing by hand gives you a little more room for creativity. Here are some suggestions:
* Scrape the dishes thoroughly over the trash can or scrap bin.
* Fill the sink with warm soapy water and dip the dishes, or fill a cup with warm soapy water and dip the brush or sponge.
* Plug the sink and turn on the cold water. Hold soapy dishes under the tap to rinse them until the sink is half full. Then turn off the water and dip the dishes to rinse them.
* Let the dishes air dry on the rack. Hand drying is boring and unnecessary -- unless you need an excuse to stand at the sink and chat with someone in particular.
Automatic dishwashers can't provide this romantic opportunity, they break down, they are expensive and they use more `D electricity. But from my rigorously unbiased standpoint, of course, whatever you want to do is fine. Especially if what you want to do includes washing my dishes.