October 19, 2017
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What’s the Most Eco-Friendly Dishwasher Cycle?

By Ask Umbra®, Grist.org


Q. Dear Umbra,

With regards to dishwasher cycle times vs. power and water usage, is it better to run the normal cycle (1:43 to 2 hours) that uses less water but more power, or the 1-hour cycle that uses less power but more water?

Rene S.
Litchfield Park, Arizona

A. Dearest Rene,

Are you, by any chance, eyeing an overflowing sink of dirty dishes right now? Or dreading the overflowing sink to come after ringing in the new year this weekend? Or both? I do love revelry with friends and family, but my, we certainly pay the piper in the form of cleanup. My usual position is that careful hand-washing is the best way to get those dishes sparkly, but sometimes the task is just too daunting. For those times, we turn to the magic of the dishwasher — and the confusion of its many cycle settings.

It’s difficult to say for sure without knowing what kind of dishwasher you have, Rene, but it’s likely that the normal-versus-express-cycle question is more straightforward than you think. Generally, a one-hour cycle will use more water and power to polish up your place settings. Why? The dishwashers of yesteryear gulped much more water and energy than today’s more modern models: We’re talking more than 10 gallons of water per cycle, compared to 3 gallons or less with the best new Energy Star appliances. When federal efficiency standards started demanding improvement on both electricity use and water use in the ‘90s, dishwasher manufacturers found they could meet the new guidelines without compromising cleanliness if they made wash cycles longer, allowing enough time for a thorough scrubbing.

I checked out stats on a few dishwashers from Kenmore, Bosch, and GE, and in all of those cases, their shorter cycles use more water and electricity. The difference can be stark: This one, for example, uses as little as 2.4 gallons on the 2:21-hour normal cycle, but chugs through 7.9 gallons on the 1-hour wash. Talk about patience being a virtue, eh? You’ll have to check your machine’s manual to be certain (you can probably find it online if you don’t have it stuffed in a drawer somewhere), but my guess is your dishwasher packs similar stats.

But our dish decision-making isn’t quite over yet. What about all those other settings? Can we do anything else to green up our cleanup? Why yes! Here are some dishwasher best practices:

  • First, the basics: Never run the dishwasher with anything less than a full load, and scrape but don’t pre-clean dishes before loading them in. Older models required pre-cleaning, but newer dishwashers have more efficient designs and souped-up filtration systems to handle any lingering traces of your special Bolognese sauce.
  • Steer clear of the Pots & Pans and Heavy-Duty cycle settings: These ones usually bring tons of water to the task of sudsing up the grimiest dishes. Better to let particularly dirty dishes soak in the sink before washing. Also avoid the Sanitize cycle unless absolutely necessary (i.e., someone in the house is sick, or you need to sterilize baby bottles) — this one fires up with extra-hot water, which boosts energy use accordingly.
  • Do use Auto (aka Sensor, SmartWash, or any number of clever branded names), a high-tech setting that detects how dirty the dishes are and adjusts cycle length, heat, and water to match. And if you have an Eco cycle, by all means use it to save both power and water.
  • You know that Rinse setting? Don’t do it. Such a cycle just splashes extra water on dishes you’re not quite ready to wash, then runs through a full cycle later, when you are.
  • Pick Air Dry instead of Heat Dry — good old evaporation dries your cups and spoons just as well as extra heat, but uses as much as 50 percent less power. No Air Dry setting? Turn the dishwasher off at the end of the cycle and open the door to MacGyver it.

May your new year be filled with joy, progress, friendship, and efficiently washed dishes, all!

Sparklingly,
Umbra