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Noise and air source heat pumps

Advice on installing air source heat pumps so noise will not cause complaints

People are increasingly installing air source heat pumps (ASHP) to help heat their properties. They provide a low carbon heating solution reducing energy bills. Switching out fossil fuels is also key to the UK’s plans to achieve net zero by 2050.

Whilst ASHP are good news for the environment, they can be noisy, giving rise to complaints.

Installation of an ASHP in a domestic premises is considered to be permitted development provided the installation complies with the Microgeneration Certification Scheme planning standards (MC20) or equivalent. The noise standard to be met at the nearest neighbour is 42dB LAeq, 5 mins. However, despite meeting this standard, it is not uncommon for ASHPs to give rise to complaints after they have been installed.

The problem is the MC20 standard does not take into account the spectral content/frequency or any tonal characteristics of the noise and uses a default background noise level of 40dB rather than a measured background level. Background noise levels during the night in more rural areas in Waverley can get down to 25 dB(A) or less. 

If the noise from an ASHP is causing a statutory nuisance, despite meeting the MC20 standards, the council has a duty in law to take action to try and abate the nuisance.

Ensuring your ASHP will not cause noise problems

We recommend the following to try and make sure your ASHP will not cause noise problems: 

  • Install the ASHP away from neighbouring property. Noise levels reduce with distance away from a source.
  • Refer to the IOA and CIEH Professional Advice Note on Heat Pumps which gives further guidance on minimising the likelihood of noise complaints and recommends a maximum sound rating level of <35dB at any noise sensitive neighbouring premises
  • Ask your installer to undertake a noise assessment before you install the ASHP, to make sure noise levels from it will not cause a statutory nuisance to neighbours. This will take into account background noise levels, the characteristics of the noise, volume on all settings including defrost, distance from the ASHP to the nearest neighbour, and any noise barrier/mitigation present.
  • If installation of a ASHP requires planning permission and we are concerned it might cause noise problems, we will recommend the following to the Local Planning Authority:

1. The noise standard to be met

Noise resulting from the use of the ASHP shall not exceed a level of 5dB LAeq below the existing background level when measured according to British Standard BS4142:2019 (or as updated), at a point one metre external to the nearest noise sensitive premises.

(This is in line with the Local Plan Part 2: Site Allocations and DM Policies (Adopted on 21 March 2023))

2. A noise assessment is undertaken

Before the development commences (installation of the ASHP) the following shall be submitted to the Local Planning Authority:

(a) The findings of a noise survey (undertaken in accordance with BS 4142 or such other standard acceptable to the Local Planning Authority) to determine noise levels in the vicinity of the proposed development;

(b) Written details and calculations showing the likely impact of noise from the development

(c) If needed, a scheme of works or such other steps as may be necessary to minimise the effects of noise from the development;

(d) The development shall not commence until written approval of a scheme under (c) above has been given by the Local Planning Authority. All works forming part of the scheme shall be completed before the ASPH is operational.

Further advice

Please contact Environmental Health for further advice at