Noise calculator: How loud is the heat pump at the neighbour's?

The most common point of dispute with air-source heat pumps — and one that can almost always be solved by choosing the right installation location. Important: The decisive factor is the level at the neighbouring property, not the number in the brochure.

Sound power level of the device (L_WA) 54 dB(A)

40 — very quiet75 — loud

Found in the data sheet, often as "L_WA" or "sound power". Modern devices are around 50–60 dB(A). Not the value "xx dB at 1 m distance" — that is the sound pressure and is about 8 dB lower.

Distance to the neighbour's window / property boundary 5 m

1 m30 m

Installation situation

Freestanding in the gardenNo building in the immediate vicinity Against a house wallOne reflecting surface, +3 dB In a corner of a buildingTwo reflecting surfaces, +6 dB — avoid if possible

Night setback / silent mode off

off−10 dB

Acoustic enclosure / protective wall none

none−12 dB

Only works if the direct line of sight to the neighbour is interrupted. A wall that you can see over achieves almost nothing.

Zoning of your area

Quiet area / spa area — 35 dB at nightRecreation areas, health resorts Residential area on the outskirts — 40 dB at nightSingle-family housing estates, suburbs Urban residential area — 45 dB at nightDenser residential development in cities Core area (residential + commercial) — 50 dB at nightTown centres, mixed-use areas Commercial/industrial area — 55 dB at nightCommercial spaces

Guideline value met

Level at night at the neighbour's: 36,2 dB(A)
Guideline value at night: 45 dB(A)

Reserve at night+8,8 dB

Level during the day41,2 dB(A)

Required minimum distance2,1 m

Notes

Clarify installation with installer

Free-field calculation without shielding by buildings and without air damping — i.e. the conservative approach. The assessment by the authority or experts according to ÖAL-Richtlinie Nr. 3 (Austrian noise protection guideline) is binding.

Site plan from above

The coloured circle is the area in which the night-time guideline value is exceeded. If the property boundary lies outside of it, you are on the safe side.

How it is calculated: The sound pressure level at the point of immission results from the sound power level of the device, the distance and the directivity caused by reflecting surfaces: L_p = L_WA + 10·log₁₀(Q / 4πr²). Every doubling of the distance brings about 6 dB — twice as far away is therefore almost always more effective and cheaper than any noise protection measure. The guideline values come from ÖNORM S 5021 (Austrian standard); some federal states additionally link the public grant to noise limits, for example Vorarlberg to a maximum of 55 dB sound power. Details in the public grant check.