Wednesday May 6, 2015
It is still common practice in many households to - after dinner - wash the dishes by hand to get all the grimy food off of them, and then put them in the dishwasher and run a cycle. For many of us, it just feels cleaner. And that can be a very personal feeling, hard to let go of.
The problem is, a diverse group of experts - including from Consumer Reports, the Environmental Protection Agency's Energy Star Program, the Natural Resources Defense Council, the American Council for an Energy-Efficient Economy - suggests that in most cases we should just "let the dishwasher do its job," as Consumer Reports puts it.
The basic line is that from an environmental perspective, these machines have grown so energy- and water-efficient - especially Energy Star-certified models - that it is very hard to beat them through hand-washing (though, of course, you should first scrape off any food before putting dishes in the dishwasher, and you should run only full dishwasher loads).
The reasons for this are multiple, but they include the fact that dishwashers just keep needing less and less water (and energy) because of improving appliance standards, even as they get better and better at using it.
"While it may be possible to use less water/energy by washing dishes by hand, it is extremely unlikely," Jonah Schein, technical coordinator for homes and buildings in the EPA's WaterSense program, said in a statement. Schein was referring, in particular, to Energy Star-certified dishwashers, not all dishwashers.
"In order to wash the same amount of dishes that can fit in a single load of a full size dishwasher and use less water, you would need to be able to wash eight full place settings and still limit the total amount of time that the faucet was running to less than two minutes," he said.
"Studies are showing more and more that, when used to maximise energy-saving features, modern dishwashers can outperform all but the most frugal hand washers," adds the American Council for an Energy-Efficient Economy.
How well modern dishwashers conserve water and energy is not the same thing as how well they perform their cleaning task. And determining how clean is "clean enough" is somewhat subjective. But here, too, the machines have a number of advantages.
For instance, our hands just can't take the hot water temperatures - 140 or 145 degrees Fahrenheit (60 or 62 degrees Celcius) - that many dishwashers use to get stuff really clean.
Modern dishwashers also often include an increasing number of high-tech features that are just better at cleaning than we are - the design of the racks, the spray of the water jets and other aspects have been tailored to improve performance.
The overall story here is a familiar one in the appliance world, and much like what has happened with refrigerators: Ever increasing standards have made dishwashers more and more energy- and water-efficient, even as they've also taken on new features, such as soil sensors, which detect whether your dishes are still dirty.