If you grew up watching your parents wash every dish by hand to save money, I’ve got bad news. They were paying extra for the privilege.
That’s not my opinion. It’s the federal government’s math. Energy Star, the federal energy-efficiency program, says a certified dishwasher can trim about $220 a year off your utility bills compared with washing by hand.
Over the life of the machine, that adds up to about $3,300. That’s real money, poured down the drain one sinkful at a time.
The problem isn’t you. It’s advice that made sense decades ago and never got updated. Dishwashers changed. The folk wisdom didn’t. Here’s what the numbers actually say, and the habits that make the savings even bigger.
1. The sink costs more than the machine
Start with what it costs to run a dishwasher. Energy Star puts a standard-size certified model at about $50 a year. That’s less than a dollar a week.
Now look at the water. Standard-size certified dishwashers are allowed to use no more than 3.2 gallons per cycle, under Energy Star’s current standards, which took effect in July 2023.
Compare that to your kitchen faucet. Federal rules cap kitchen faucets at 2.2 gallons per minute, according to the EPA. So every minute the tap runs while you scrub and rinse can pour out up to 2.2 gallons — and if it’s hot water, you paid to heat it, too.
Do the math and a full dishwasher cycle uses about what a wide-open faucet pours out in less than a minute and a half. Nobody washes a day’s dishes in 90 seconds.
Energy Star says switching from hand-washing to a certified machine saves about 8,400 gallons of water a year. At 2.2 gallons a minute, that’s like leaving your faucet wide open for about 64 hours straight.
Then there’s your time. Energy Star estimates a certified dishwasher saves more than 230 hours a year. That’s nearly 10 full days — an entire vacation — spent standing at the sink.
If you’d like to see how much your water bill has climbed, it’s worth reading about why water bills keep rising and how to cut yours.
2. Stop pre-rinsing your dishes
Here’s the habit that undoes a lot of the savings: rinsing everything before it goes in the machine. Plenty of people basically hand-wash the dishes, then run them through the dishwasher anyway. That’s paying twice.
Energy Star says rinsing before loading raises the total amount of water and energy you use. Its advice is simple: Scrape the food off and load the dish.
If dirty dishes are going to sit overnight, use the dishwasher’s rinse feature instead of the faucet. Energy Star says that setting uses only a fraction of the water you’d need to rinse by hand.
Scraping matters for the machine, too. For more ways to protect your investment, see “1 in 5 Dishwashers Fail Within 5 Years. 7 Habits That Make Yours Last.”
3. Wait for a full load
A dishwasher doesn’t care whether it’s washing four plates or 40. It uses roughly the same energy and water whether it’s packed or nearly empty.
That means running it half-empty basically doubles your cost per dish. Wait until it’s full, then run it.
The Department of Energy adds one caveat: It should be full, not overloaded. Cram it so tight that water can’t reach everything, and you may end up washing some of it again by hand — which defeats the whole point.
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4. Turn off the heated dry
The heated-dry setting uses extra energy to do a job that air does for free. I’d turn it off and never look back.
The Department of Energy recommends letting dishes air-dry instead. Energy Star notes that some models let you switch heated dry off entirely.
If you’re worried about spots, crack the door open when the cycle ends. A little patience costs nothing.
5. Pick the lighter cycle when you can
Not every load needs the pots-and-pans treatment. Breakfast plates and coffee mugs don’t need the heaviest cycle your machine offers.
Energy Star notes that choosing a light cycle when dishes are only slightly dirty uses less water. The Department of Energy likewise suggests choosing more efficient cycles for loads that aren’t heavily soiled.
One more trick worth checking: Some dishwashers have a built-in heating element that boosts the water temperature on its own. If yours does, the Department of Energy says you can turn your water heater down to 120 degrees. Check your owner’s manual first.
Turning the water heater down can trim the cost of every shower and sink, too. Here’s more on what your water heater costs and how to chill the bill.
6. Got an old dishwasher? Look for a rebate
Everything above assumes a reasonably efficient machine. If yours is old enough to remember the last century, the math may not be as favorable.
Before you shop, check Energy Star’s Rebate Finder. Enter your ZIP code and it shows rebates and special offers on certified products near you, including dishwashers.
When you compare models, look at the yellow EnergyGuide label to see how much energy each one uses. And unless you live alone, think twice about a compact model. Energy Star says their smaller capacity can mean more energy use over time than a standard-size machine.
The bottom line
Being frugal is about results, not rituals. Washing dishes by hand feels thrifty, but the government’s numbers say it costs more money, more water and more of your life.
So scrape, load it full, skip the heated dry and hit start. Then go do something better with those nearly 10 days.
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