How Loud Is a Dishwasher? What the Energy Label Declares

A dishwasher's declared noise figure is a sound power level. Sound power describes the total acoustic energy a source radiates, independent of the room it sits in, how far away you are standing, or what the walls are made of. It is a property of the machine.

Sound pressure — the quantity a sound level meter reads and the quantity your ears respond to — depends on all of those things. The two are different physical quantities with different reference values, and the energy label deliberately declares the first, because it is reproducible in a test laboratory and comparable between brands.

This is why the unit matters. A declared 44 dB(A) re 1 pW is not a promise that you will measure 44 dB(A) in your kitchen. It is a laboratory-determined emission figure, measured to the method in the IEC 60704 test-code series, filed by the manufacturer under EU labelling law.

Regulation (EU) 2019/2017 sets four bands. They apply to the eco programme, which is also the programme used for the label's energy and water figures.

The declared figure describes the eco programme. That programme runs long and gently by design, because the label rewards low energy and water use.

An intensive or short programme uses more spray pressure and more pump activity, and there is no requirement to declare a figure for it. So the label's number is the machine's quietest routine operating condition rather than its worst case, and the drain phase — which is what most people actually notice through a kitchen wall — is not separately declared at all.

None of the sources we reviewed publishes measured levels for individual dishwasher programme phases in a way that could be compared with the declared value.

We looked for a published sound pressure level for a dishwasher at a stated distance, with a stated weighting and stated room conditions, from an agency, standards body or peer-reviewed study. We did not find one.

Academic work on dishwasher acoustics exists — vibro-acoustic source analyses, sound-quality studies — but it studies noise paths and perception rather than publishing a reference level for a kitchen. So the honest position is that the declared sound power is well documented, and the level at your sink is not.

That is also why we will not tell you that a class-A dishwasher "sounds like a whisper". Whispers are quoted as sound pressure, the label is sound power, and putting the two in one sentence is the exact error this page exists to avoid.

Measuring your dishwasher is genuinely useful for comparing states — door closed against door ajar, wash against drain, kitchen against next room — because the comparison does not depend on absolute accuracy.

What it cannot do is verify the label. Uncalibrated our meter reports A-weighted digital signal level in dBFS, which is relative rather than sound pressure; after a one-time local calibration it reports an estimated dBA figure. Neither is a sound power measurement, which requires either a reverberation room or a measurement surface of microphones around the source.