Only one maker comes close to the full picture, and a bare or lightly conditioned dBA is the norm.
| Maker | Published figure | Conditions attached |
|---|
| GE Profile | "as low as 41 dBA" | NEEA Advanced Water Heating Specification 8.1; a floor for a variable speed compressor |
| Rheem, Ruud, Richmond | 45 dBA | "measured at 6.28 feet using third-party certified testing procedures" |
| AO Smith | 45 dBA | None |
| Bradford White | "less than 50 dBA" | A bound, with no condition |
| Stiebel Eltron | 60 dB sound power, 52 dB(a) sound pressure | Pressure at 3.3 feet (1 m), with a footnote on the two quantities |
| Rheem 120V plug-in | 55 dBA | A column in the spec table |
Rheem, Ruud and Richmond are three badges on one platform, and they share the best footnote in the class. GE's specification is a real step, yet "as low as" still describes the quietest moment of a variable speed compressor rather than a constant. AO Smith's 45 comes with nothing at all.
Stiebel Eltron alone prints "Sound power level* 60 dB" and "Sound pressure level* @ 3.3 feet (1 m) 52 dB(a)", plus a footnote explaining the difference.
Stiebel Eltron's fuller disclosure reads worse
Stating the conditions costs Stiebel the comparison. Its 52 dB(a) is sound pressure at 1 meter, while Rheem's 45 dBA is taken at 6.28 feet, about 2 meters, where sound pressure reads lower. Set side by side, the two look 7 dBA apart. They are two different measurements at two different distances, and neither outranks the other. How the two quantities differ is laid out in the sound power vs sound pressure explainer, and our note on lining up water heater ratings from rival brands covers the distance problem.
Who makes the quietest heat pump water heater?
GE, by published number: "as low as 41 dBA" against the 45 that AO Smith, Rheem, Ruud and Richmond claim. A floor figure and an unconditioned constant are hard to referee, though.
GE's GeoSpring page claims the class lead at that 41, and its brochure repeats "Quiet operation at just 41 dBA." Meanwhile AO Smith's Lowe's line claims the "Quietest Hybrid Electric Heat Pump on the market at 45 DBA". Those two claims contradict each other. A four decibel gap between figures taken under unstated and different conditions proves nothing about the machines themselves, but AO Smith's marketing sentence does not survive GE's published spec.
The fight is still a good sign. This category considers quiet worth competing on, which is more than the refrigerator aisle can say.
Rheem's 120V plug-in prints 55 dBA
In the sound level column of its spec sheet, Rheem's 120V dedicated circuit model prints "55", ten dBA above the 45 it claims for its own 240V hybrid. A compressor with no backup elements has to work harder.
The new 120V plug-in hybrids solve an electrical problem, since they need no 240V circuit, and Rheem's sheet puts a number on what that costs in noise. The other makers either match or stay silent. AO Smith claims its 120V Voltex runs at the same 45 dBA as its 240V unit, GE's line wide floor covers its 120V models too, and nobody else numbers a 120V unit at all.
Near living space, the 240V hybrid is the safer bet for noise, and Rheem's own disclosure is the evidence.
That goes double for a basement that also serves as a bedroom, office or gym. Our page on keeping a quiet basement sets the water heater beside the dehumidifier, freezer and laundry that share the room.
