How loud is a heat pump, and where is the best place to install it?
In short: According to the data sheet, the air-to-water heat pumps in the range have a sound power level ranging from 60 dB(A) at 8 kW to 68 dB(A) at 16 kW. How loud it sounds at the bedroom window or at the neighbour’s depends primarily on the installation location: According to dena, the noise level drops by around 6 dB(A) for every doubling of the distance; according to the German Heat Pump Association, nearby walls increase the level by 3 dB(A) compared to a unit positioned freely against a wall, and by 6 dB(A) when positioned in a corner. It is best to position the unit freely, at a distance from bedrooms and with the air outlet facing away from the house.
Contents
Sound power and sound pressure
An air-to-water heat pump is installed outdoors, and its fan and compressor can be heard. How loud it ultimately is depends less on the unit itself than on its location. This page explains the values in the data sheet, works through an example and outlines what is important when installing the unit.
The sound power is stated in the data sheet and on the energy label. According to the German Heat Pump Association (BWP), this is a measure of the sound source, independent of distance and direction. What you hear at a window is the sound pressure; this always depends on the distance from the unit.
The air-to-water heat pumps in the range, according to the data sheet, are:
| Performance class | Sound power | Manufacturer |
|---|---|---|
| 8 kW | 60 dB(A) | Hantech and TCL |
| 10 kW | 61 dB(A) | Hantech and TCL |
| 12 kW | 64 dB(A) | Hantech and TCL |
| 16 kW | 68 dB(A) | Hantech and TCL |
Information current as of: ACTEC product range, October 2026. Hantech units operate using the refrigerant R290, whilst TCL units use R32; according to the data sheet, there is no difference in their sound power levels. An information sheet from the State of Brandenburg points out that the value on the energy label does not always correspond to the highest sound power level. If in doubt, ask the manufacturer for the maximum value.
What distance and walls make up
- Distance: According to DENA, doubling the distance reduces the sound pressure level by approximately 6 dB(A).
- Walls: Walls reflect sound. The BWP calculates a 3 dB(A) penalty for a freestanding appliance located less than 3 m from a wall, 6 dB(A) when placed against a wall, and 9 dB(A) when placed in a corner.
A rough calculation based on the formula in the BWP’s noise guidelines for a device with a sound power level of 61 dB(A), excluding surcharges for tone quality and quiet periods:
| List | at a distance of 5 m | at a distance of 10 m |
|---|---|---|
| freestanding | around 39 dB(A) | around 33 dB(A) |
| on a wall | around 42 dB(A) | around 36 dB(A) |
| in a corner | around 45 dB(A) | around 39 dB(A) |
There is therefore a difference of 6 dB(A) between free-standing and corner installation, which is exactly the same as the difference between distances of 5 and 10 metres. For your specific case, use the noise calculator provided by the German Heat Pump Association, which takes into account the unit, the installation location and any screening.
What to bear in mind when compiling the list
- Distance from bedrooms and neighbours: According to the Consumer Advice Centre, the appliance should not be placed in the immediate vicinity of bedrooms or neighbouring buildings.
- Not in corners and recesses: according to the Consumer Advice Centre, echo effects occur between two walls; the BWP calculates the highest surcharge in a corner.
- Air outlet directed away from the building: According to the BWP, the direction of the airflow should not be towards rooms requiring protection, and direct airflow onto walls should also be avoided.
- Stable foundation, decoupled: The BWP lists strip foundations as tried and tested; every connection to the domestic plumbing system is acoustically decoupled to prevent vibrations from entering the house.
- Shielding: A sound-insulating hood or wall can reduce the noise level, but according to the BWP, it must not obstruct the airflow.
- Night-time operation: According to the BWP, many heat pumps have a noise-reduced operating mode via a timer programme, for example for night-time use.
Neighbours and specifications
The relevant environmental protection authority will inform you of the noise limits applicable to your neighbours’ windows. A specialist company can assist with planning the installation site; for an initial estimate, you can use the BWP’s noise calculator.
If you do not wish to heat the whole house, but only individual rooms, you can also opt for a split air conditioner; information on how noisy their outdoor units are can be found under ‘How noisy is an air conditioner?’. Whether a heat pump is suitable for an older house is explained under ‘Heat pumps in older buildings’. All units are listed under ‘Air-to-water heat pumps’. The differences between the two types are explained under ‘Air-to-air or air-to-water heat pump?’.
Air-to-water heat pumps
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