Is a dishwasher too loud? Here's what to know before buying one

Twenty or 30 years ago, dishwashers were far from quiet. Very few had any features designed to muffle the sounds coming from inside, and the sounds themselves were louder due to their built-in macerators. If you’ve ever wondered why an old dishwasher was almost as loud as your garbage disposal, it’s because it was using one. And we should know because we've tested hundreds of dishwashers in the Reviewed labs.

More recently, however, the dishwasher space has changed. Where older models averaged about 60 decibels—just below the sound level of a vacuum—modern dishwashers average between 40 to 50 decibels, which is about as loud as typing on a keyboard. It’s not completely silent, but also not loud enough to wake someone up.

One question we've pondered often is, “What is considered a quiet dishwasher?” While we don't measure it ourselves due to the specialized space required for accurate readings, we do consider it as a data point for every dishwasher we test. If you want to skip all the science and get to the recommendations of the best quiet dishwashers that also clean well, we’ve got you covered.

However, if you want to know why some dishwashers make less noise than others, we first have to start with how that noise is measured.

Decibel A-weighting: The best tool for measuring loudness

To understand how dishwashers went from being about as loud as a vacuum cleaner to being so quiet they wouldn’t get kicked out of a library, we first need to talk about dBA (decibel A-weighting).

You’ve probably heard of decibels (or dB) before—that’s the logarithmic unit of measurement to determine loudness. The most common unit to measure noise levels is called decibel A-weighting—denoted by dBA. In its most simplistic terms, dBA is a sound curve based on human hearing. Here’s a quick list to put dBA values into perspective:

• 0 dBA: The threshold of human hearing
• 25 dBA: Whispering
• 40 dBA: Suburban area at night
• 70 dBA: Vacuum cleaner
• 105 dBA: Lawnmower
• 140 dBA: Jet engine at 100’

So, as you can see, dBAs can go from zero to extra-loud pretty quickly. The dBA scale is a more intuitive and helpful way to determine what we’re more likely to perceive as loud and quiet.

What is the decibel level of a quiet dishwasher?

Unlike other manufacturer-supplied metrics (looking at you refrigerator capacity measurements), you can trust stated dBA measurements: They’re all measured by a third-party, Owens Corning. Owens Corning has labs dedicated to accurately measuring how loud a given appliance is and decades of experience doing so.

Let’s say you were looking at the Bosch 800 Series SHP78CM5N at Home Depot. It says 42 dBA at the top of the page. This means that Owens Corning determined that, on average, this dishwasher will produce 42 dBA of noise—or about the same as a suburban street at night.

When we tested the 800 series in our labs, we could have a conversation in front of it while it was running and barely notice it was there.

What makes a dishwasher quiet?

While there are many factors that go into how loud a dishwasher runs, the number one factor in the dBA of a dishwasher is usually the material the interior is made of. Plastic dishwashers are much louder than stainless-steel ones.

For example, the Whirlpool WDF330PAHW has a completely plastic interior. It has a sound rating of 55 dBA. During testing, it sounded like someone was taking a shower in there—not super loud, but you definitely knew it was running.

Compare that to a hybrid tub which is steel on the sides and plastic on the bottom, like the Bosch 100 Series SHE3AEM5N, and the sound rating decreases to 50 dBA.