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How noisy is an air source heat pump?

A modern domestic air source heat pump typically produces around 45 to 55 decibels at one metre, dropping quickly with distance. Nuisance complaints usually come from poor siting close to bedroom windows or enclosed courtyards rather than the unit itself.

The exempted development conditions for heat pumps include a noise limit at the nearest neighbouring dwelling, so noise is a planning matter as well as a comfort one. Manufacturer sound power data should be checked against the separation available.

Defrost cycles in cold weather are noticeably louder than normal running, and that is when complaints tend to arise. Site the unit away from bedroom windows on both properties and avoid tight corners where sound reflects.

Reducing noise impact

  • Maximise distance from windows and boundaries
  • Avoid mounting on a lightweight wall that can transmit vibration
  • Use anti-vibration mounts and a solid base
  • Avoid enclosing the unit in a way that restricts airflow

Sources

Last reviewed 28 August 2026. General information only — not legal or planning advice.

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