How Dishwasher Noise Is Tested: dB Standard Procedures

Why the dB rating on a spec sheet is a starting point

The decibel (dB) rating you see on a dishwasher spec sheet is a measurement of sound pressure taken in a laboratory, not in a home kitchen. The number tells you how loud the machine is during a defined wash cycle, and lower numbers indicate less noise. Since every model is measured in a comparable way, the rating gives you a consistent basis for comparing one model with another.

No official federal standard specifies how a dishwasher must be tested for noise, unlike the energy and water test method required by the U.S. Department of Energy. That means two different brands can quote their own test results, and the numbers are not always directly comparable across brands. You should still use the dB rating as your first filter, then look at the model's feature set.

The decibel levels and what they mean page explains why a lower number is not always the only thing that matters.

The federal test method for dishwashers

ENERGY STAR certification for dishwashers is based on a test method defined by the Department of Energy in 10 CFR 430, Subpart B, Appendix C1, according to the ENERGY STAR key product criteria page. That procedure went into effect for all models on January 23, 2024, and it measures energy use and water consumption, not noise. The average number of cycles per year used in the calculation is 215.

Because the federal test method does not cover sound, the dB figure you see on a spec sheet comes from a separate laboratory test conducted by the manufacturer or a third party. There is no single mandatory standard, but in practice you can expect the rating to be captured during a normal wash cycle with a full load. The exact conditions are not always disclosed, so the most reliable way to compare is to look at the dB number alongside the brand's own description of the test.

For a deeper look at how the federal program works, see the ENERGY STAR requirements for dishwashers and how to compare dishwasher specs.

What the dB test measures and what it leaves out

A decibel is a unit of sound pressure, and for dishwashers it is usually reported as an A-weighted value, which approximates how the human ear perceives loudness. The scale is not linear, so a difference of a few dB is clearly noticeable. A machine rated a few decibels lower will sound meaningfully quieter in real use.

The test number captures the sound of the spray arms, water circulation, and motor, but it does not capture the sound of your dishes rattling, the plumbing in your walls, or the echo of a small closet. It also does not include installation factors such as how tightly the unit is mounted or whether there is a gap in the countertop cutout. Use the dB figure as a baseline, not a guarantee.

If you are deciding between two neighboring ratings, the 44 dB vs 48 dB comparison can help you judge whether the difference matters.

Sones versus decibels

Some manufacturers quote sound in sones rather than decibels. A sone is a measure of perceived loudness that tries to account for the way your ear responds to different frequencies. The two scales are related, but they are not interchangeable, and the manufacturer will state which one is being used.

When you see a sone figure on a spec sheet, you can still use the same rule: lower is quieter. If the manufacturer provides both numbers, compare on the scale that is stated rather than trying to convert between them. The dishwasher dB rating explained article covers how the two units relate in practice.

How to compare noise ratings across brands

Because there is no mandatory federal test for dishwasher sound, you should treat the dB number as one of several specifications, not as an absolute truth. A model rated in the mid-40s may be quieter in practice than another model with the same number if the test conditions differ. The most effective way to narrow your choices is to set a target range based on the dB number, then read the details of the wash system, insulation, and motor type.

For an open kitchen or a living space adjacent to the kitchen, you will likely want a model at the quieter end of the scale. For a closed utility room or a basement, a higher rating may be perfectly acceptable and may cost less. If you are replacing an existing unit, you can install anti-vibration pads and make sure the unit is level, but the largest factor is the dishwasher's own design.

Browse quiet dishwashers, models rated up to 44 dB, 45 to 49 dB models, and 50 dB and above to see what your target range offers.

What to listen for if you see a model in person

A showroom is not a good place to judge dishwasher noise because the ambient sound level is much higher than in a home, and the unit is not installed in a cabinet. If you can hear a running dishwasher in a store, you can get a rough sense of the tone and the amount of water noise, but you should not decide based on that alone.

Instead, rely on the dB figure and the brand's own claims. Brands that emphasize quiet operation tend to put more engineering into insulation, the motor, and the spray arm design. A stainless steel tub absorbs sound better than a plastic tub, though it is not a guarantee of lower noise. You can also learn about the materials and design choices that reduce noise.

What to pick for your use

Questions

Is there a government standard for dishwasher noise?

There is no federal test method that requires a specific dB rating. The Department of Energy test procedure for dishwashers, defined in 10 CFR 430, Subpart B, Appendix C1, covers energy use and water consumption, not noise. Noise is reported by the manufacturer based on its own lab test.

What is a good dB rating for a dishwasher?

There is no single good number because the test conditions are not standardized across all brands. In general, lower dB ratings mean quieter operation, and a model rated in the mid-40s is considered quiet for a built-in. Compare ratings only within the same brand or look for models that state their test method.

Why do two dishwashers with the same dB rating sound different?

The dB number captures overall sound pressure but not the tone or the distribution of noise. One model may have a high-frequency hum while another has a lower whoosh, and your ear will perceive them differently. Installation and cabinet design also change the sound.

Does a stainless steel tub make a dishwasher quieter?

Stainless steel is denser than plastic and tends to absorb vibration, so it can reduce the transmitted noise. But the motor, insulation, and spray arm design play a larger role, so a plastic-tub model with a well-insulated design can still be quiet.