If you’ve avoided dishwashers because you think they waste water, use too much electricity, or don’t clean well, it’s time to set the record straight.
Energy Star–certified dishwashers use a maximum of 3.2 gallons of water per cycle on the “normal” setting, while hand-washing the same number of dishes typically uses around 25 gallons.
One “place setting” consists of five pieces—usually one dish, one cup, and a set of cutlery. A standard-size dishwasher holds–at minimum–eight place settings and six serving pieces, totaling 46 items.
It takes the average person about 15 seconds to clean and rinse each dish by hand, so washing 46 pieces takes around 11.5 minutes. U.S. kitchen sinks have a flow rate of 2.2 gallons per minute, and because most people keep the water running while washing, this results in 25.3 gallons of water used for hand-washing.
Can a dishwasher clean effectively with just 3.2 gallons? Absolutely!
Chemist Dr. Herbert Sinner identified four factors necessary for effective cleaning: time, temperature, chemical action, and mechanical action. Dishwashers compensate for the lack of mechanical action (scrubbing) by boosting water temperature, extending wash time, and relying on stronger chemical action from detergent. The heater used to boost the water temperature also uses much less electricity than that used by a water heater to constantly heat water during hand-washing, making dishwashers more energy-efficient as well.
Proper dishwasher use and maintenance are key to getting the best results. Here’s how to optimize performance:
- Face the dirty side of dishes toward the spray arms (where the water comes out to spray dishes)
- Leave space between dishes to prevent them from “nesting” into each other
- Avoid placing dishes parallel to the door to ensure detergent dispenses properly
- Make sure no dishes are preventing the spray arms from spinning freely
- Point cutlery upwards (handles down), but knives point-down for safety
- Clean the filter and run a dishwasher cleaner monthly
- Follow the instructions on the detergent packaging for best results
Bonus tip: Most dishwasher manuals include a diagram showing how to load dishes in your specific model for optimal cleaning!
