Dishwashers are already pretty efficient—so why the new rules?
By clicking one of our links you're supporting our labs and our independence, as we may earn a small share of revenue. Recommendations are separate from any business incentives.
Last year, the Department of Energy proposed new efficiency standards for dishwasher manufacturers. Unsurprisingly, industry representatives weren't very thrilled.
In statements made to The Hill last month, Rob McAver of the Association of Home Appliance Manufacturers (AHAM) said, "At some point, they're trying to squeeze blood from a stone that just doesn't have any blood left in it." He went on to add that "the poor performance that would result would totally undercut and go backwards in terms of energy and water use, because of the need for running the dishwasher again, or pre-rinsing or hand-washing, which uses a lot of water."
Is he right? We at Reviewed.com are uniquely equipped to tell you. AHAM—whose members include industry titans like GE and Whirlpool—has created many standardized testing methodologies, some of which we've adapted for use in our own labs. We've been testing these machines for a while now, and our data goes back years. Here's what it tells us.
Federal regulations are inherently complicated, but here's all you really need to know: The new rules call for a limit of just 3.1 gallons of water per wash cycle. Whether that's enough to reliably get dishes clean is the primary point of contention between AHAM and the DOE.
Note that the proposed limit is on the weighted average of all cycles used throughout a typical year of dishwashing, including less common cycles like 1-Hour Wash or Heavy Duty. These cycles factor into the calculation, but not as much as your garden variety Normal cycle.
The DOE estimates that this new, stricter limitation will save 240 billion gallons over a 30-year period, and also reduce the output of air pollutants from power generators, including carbon dioxide, methane, and other greenhouse gasses.
To put that in perspective, the previous standard was 5 gallons per cycle, meaning the new regs represent a 38 percent decrease in water usage. Electricity standards will also be tightened by 22 percent.
How much is 3.1 gallons, really? It doesn't sound like enough to clean a full load of dishes. Or does it? Does the average homeowner even know, or care?
It may surprise you to learn that the best-performing dishwasher we've ever tested, the Electrolux EI24ID50QS, doesn't use an absurd amount of water to achieve its stellar results. It actually hews very close to the previous DOE standards, using 5.5 gallons of water to run its Normal cleaning cycle. The excellent Bosch SHE8PT55UC, meanwhile, already goes above and beyond the proposed new standard at 2.49 gallons per Normal cycle, as does the KitchenAid KUDE48FXSS at 2.96 gallons.
With new technology, surely the industry could get those numbers down even further. And where are manufacturers supposed to find this technology, you ask? Well, Whirlpool already has it. Its KitchenAid KDTE554CSS includes a feature called AquaSense, which filters the water used to rinse dishes at the end of one cycle and recycles it to spray stains off dirty dishes the next time around. This model uses just 1.6 gallons of water per Normal cycle, and cleans pretty well too.
So it's possible to build a dishwasher that uses less than 3.1 gallons of water per cycle. That's great. But to many experts, dishwashers seem like strange targets for additional efficiency regulation. That's because the dishwasher is the only appliance in your home that inherently conserves resources.
Let's use an extreme example to illustrate the point: Last month, we reviewed the Maytag MDB8969SDM, which boasts a "PowerBlast" cycle that uses a ludicrous 10 gallons of water. How does this remarkably inefficient cycle compare to sink-washing by hand?
According to a 2011 study from the University of Bonn, the average person uses a whopping 40 gallons of water and 3.5 kWh of electricity washing plates by hand—per session! Earlier this year, Mother Nature Network concluded that hand-washing 10 loads of dishes uses more energy than manufacturing a modern dishwasher. It's almost enough to make PowerBlast seem green.
Water waste is a far bigger issue in other appliance categories—washing machines, for example.
When it comes to dishwashers, our data shows that extremely efficient models rack up about $25 in total utility costs per year, while the most profligate—like the aforementioned Maytag—still only cost you $41. Compare that to washing machines, where the most efficient front-load washers also cost about $25 per year but the most inefficient top-loaders run you more than $100—quite a range.
That's because the average washer uses 23 gallons per cycle, and the most wasteful top-loaders can use up to 45 gallons on their "heavy" cycles. Front-loaders that meet the most recent Energy Star regulations use just 13 gallons on a normal cycle, but that's still a far cry from the 5 gallons or less that today's dishwashers use
On a certain level, we suppose there's some merit to AHAM's position. Not much, but some. Dishwashers really do seem like strange targets for efficiency regulation. They're already among the most efficient appliances in the American home, and they're the only appliances more environmentally friendly to own than not.
Still, the DOE's decision wasn't made in a vacuum. It's not like the department has to pick one consumer appliance and regulate it. Washing machines should have tight, up-to-date standards too, and they do.
The point is, 3.1 gallons? It's just not that big a deal. Whirlpool's own dishwashers can already meet this standard. So can Bosch's. With innovations in water recycling—innovations for which there's already precedent—we could see dishwasher water needs drop below 2 gallons, without compromising performance.
While regulatory changes like this one aren't subject to congressional approval, the DOE has extended the comment period for this rule in order to work more closely with manufacturers. In other words, there's still time for everyone to give the matter more thought. But ultimately, our data shows there's not only plenty of blood left in the stone, but multiple manufacturers—including AHAM manufacturers—were already squeezing hard enough before the debate even began.