Are heat pumps noisy?
Short answer
Modern air-source heat pumps are usually designed to run quietly, but they are not silent. Noise depends on the model, fan speed, mounting and location. A compliant installation should include a noise assessment. In much of the UK, domestic heat pumps can be installed under permitted-development rules if the current planning and noise conditions are met.
Last checked 24 September 2026 · 4 sources
What does a heat pump sound like?
Most of the outdoor noise comes from the fan and compressor.
The sound varies as the unit changes output. It may be more noticeable on a cold night when the heat pump is working harder and background noise is lower.
The source interview described a 5 kW unit outside a kitchen as quiet and noted that newer fan designs have continued to improve noise performance. That is an installer’s observation, not a guarantee for every model or location.
Does every heat pump need planning permission?
No.
The interview suggests planning permission is part of every installation, but current rules are more nuanced.
England
Domestic air-source heat pumps can often be installed under permitted development. England relaxed the rules in May 2025. Qualifying installations can now be closer than one metre to a boundary, the outdoor-unit volume limit for houses increased to 1.5 m³, and detached houses can have up to two units under the right conditions.
The installation must meet the current MCS planning standard, including the noise assessment.
Wales
Wales updated its domestic heat-pump permitted-development rules on 1 June 2026. The new rules also use MCS 020(a) for sound assessment, allow up to two air-source units on detached homes and set a 1.5 m³ outdoor-unit limit.
There are additional restrictions for listed buildings, conservation areas, highways and roof locations.
Scotland
Scotland has separate permitted-development rights. One domestic air-source heat pump is generally allowed subject to conditions. Restrictions apply in conservation areas, World Heritage Sites, listed-building curtilage and some prominent roadside locations.
The installation must comply with the relevant MCS planning standard.
Northern Ireland
Planning rules are separate again. Check the current position with your local council or Planning NI before assuming permitted development applies.
How is neighbour noise checked?
The MCS planning method assesses the expected sound impact at the nearest relevant neighbouring window or assessment point.
That means a quiet model can still be a poor choice if it is badly located, while careful siting can make a significant difference.
Can vibration be a problem?
Yes. Poor mounting can transmit vibration into walls or structures.
A good installer should use the manufacturer’s mounting method and appropriate anti-vibration measures where needed.
What should I do next?
Ask for the model’s sound-power data and the completed planning/noise assessment before installation. If your property is listed, in a conservation area or unusually close to neighbours, check planning requirements early.
Sources
- Planning Portal, Planning permission: air source heat pump, checked 24 September 2026.
- GOV.WALES, Planning permission: domestic heat pumps, rules updated 1 June 2026.
- Scottish Government, Planning circular 1/2024: householder permitted development rights.
- Source interview with Heat Geek installer, noise discussion.
Last checked: 24 September 2026