Dish Wash or Hand Wash?
So, what is greener, washing dishes by hand or by machine? As with most things, there are a number of variables to consider:
Overall Water Consumption
Life Cycle Impact
Overall water consumption varies based on machine and human, and therefore, water heating goes the same way use more water, heat more water. Cleaning agents doesn't have a preference - you can find green solutions for both (see below). Electricity is easy that goes to the humans. US dishwashers are rated by EnergyStar tests with an estimated annual kilowatt-hour consumption based on an assumed 200+ cycles. The current range is from about 194 kilowatt-hours/year to around 513 so, on the best models, you are looking at just under 1 kilowatt per load that's not bad! (See an example document here.) European machines are rated with a letter-grade scale in three categories (see here for more info to help you make your purchases). As with most things, European regulations and standards are a bit ahead over the machines are more energy efficient and miserly with water. The report gives individual energy consumption per cycle and water consumption. Look for these ratings before you purchase a machine, or look them up to see how your existing machine might score. Life Cycle impact measures the energy and resources it takes to create a product and the impact from its recycling and disposal at the end of its useful life. This too goes to the hand washing. It is hard to imagine being clumsy enough to break enough dishware to have more creation and disposal impact than a dishwasher! Let's save those rinse aids and exactly what they are for another discussion. In the end, you know your own washing habits and machine better than anyone from a distance. If you are really a consistent water miser while washing by hand - keeping the water off, filling part of the sink for soaking and scrubbing and then rinsing quickly - you will probably beat a US machine that is even a few years old. When you add in the electricity and lifecycle costs, your current dishwasher just turned into an over-engineered drying rack for your hand-washed dishes. If you are like me, and try as you might, end up using more water than you would like, and live in a drought prone area, you are best off with an efficient machine avoiding a pre-rinse, using a light-wash and energy saving drying settings the 1 or 2 kilowatts of electricity will be offset by less An aerator on your faucets to restrict the flow of water to under 2.5 gallons per minute. (I have seen aerators down to 0.5 gallons per minute!) Biodegradeable and Phosphate-free soap and detergents. (Consumer Reports notes Trader Joe's and Seventh Generation Enzyme cleaners work well with dishwashers and are phosphate free. Read more here.) For those of you who like a more engineering-based perspective, check out Ask Pablo (http://www.triplepundit.com/pages/askpablo-the-dishwasher-002386.php) and conduct your own experiment human versus machine. Josh S Live Earth Green Team