How noisy is a heat pump?
Most of those who are interested in perhaps buying an air-water type heat pump will want to know how much noise the exterior fan unit of the system generates.
This concern perhaps originates from the fact that in the old days (and sometimes still today in the case of certain manufacturers), the exterior unit also contained the compressor for an air-conditioning system, which is unsuitable for use in low freezing temperatures and a noisy, high-speed fan.
This type of design generated a great deal of noise, especially in deep freeze conditions, and such systems have somewhat sullied the reputation of air-water type heat pumps.
MasterTherm CZ only uses the following types of components:
- low-speed fans with very low sound pressure levels
- quiet compressors, which are usually located with the interior unit, mounted on an anti-vibration frame
- an electronically controlled expansion valve, which significantly reduces the impact noise heard during the defrost cycle of the exterior unit
The resulting noisiness only comes in the form of a quiet buzzing of the fan.
To get a better idea of how quiet a MasterTherm CZ heat pump is, check out the following table of noise factors:
| Noise Level | Origin |
| 160 dB | space shuttle launch (up to 200 dB) |
| 150 dB | eruption of a volcano |
| 140 dB | jet plane, certain types of sirens (e.g. on big ships) |
| 130 dB | boiler shops, etc. but also the release of steam and gases under pressure |
| 120 dB | drop hammer, very noisy workshops, low flying airplanes, thunder |
| 110 dB | textile factory, noisy workshops, the inside of a large orchestra |
| 100 dB | areas in the proximity to moving trains, heavy trucks, cable cars, etc. |
| 90 dB | noisy intersections, a pneumatic drill |
| 80 dB | cars, motorcycles, noisy streets, shouting |
| 70 dB | static (non-moving) machinery |
| 60 dB | moderately noisy streets |
| 50 dB | normal conversation, quietly moving car, quiet streets |
| 41 dB | the quietest AEG dishwasher |
| 41 dB | MasterTherm CZ exterior heat pump unit (dB "A", 480 RPM, at a distance of 5m) |
| 40 dB | quiet offices |
| 30 dB | parks and quiet residential areas |
| 20 dB | whisper |
| 0 dB | pthreshold of audible sound and dead quiet |
How can you further reduce the noise of your heat pump?
To reduce the resulting noisiness of the system even further, the exterior unit of the heat pump can be mounted horizontally. This directs the sound pressure upwards, which further reduces its impact.
The exterior unit can also be installed on top of a flat roof (or even a slightly sloped roof) or outside in the garden or the back yard, where it can be surrounded with a noise barrier composed of decorative landscaping such as evergreens.