Planning and property · 6 min read
Air Conditioning Noise and Your Neighbours
Noise complaints almost always come from siting decisions, not from the equipment. Get the position right and the problem never arises.
Published 2026-07-21 · Updated 2026-07-21 · WDI Group (Surrey) Ltd
What the numbers actually are
A modern domestic indoor unit runs around 19–25 dB(A) on low fan — quieter than a fridge and below most conversation. Outdoor units typically sit in the high 40s to low 50s dB(A) at one metre, dropping quickly with distance.
At a neighbouring boundary several metres away, a well-sited unit is usually barely distinguishable from background noise.
Permitted development noise conditions
Permitted development for air source heat pumps includes a noise condition assessed at the nearest neighbouring habitable room. Manufacturers publish sound power data for exactly this purpose.
We use that data at survey to sanity-check a proposed position before anyone commits.
Practical ways to keep it quiet
Mount on anti-vibration feet or bracket pads. Avoid lightweight timber structures. Keep the discharge pointing away from boundaries and windows. Allow clearance so the fan is not fighting an obstruction.
Night mode or quiet mode on the controller reduces compressor and fan speed overnight for a small efficiency trade-off — worth it in tight terraces.
- Anti-vibration mounts as standard
- Discharge directed away from boundaries
- Acoustic screening that still allows airflow
- Night/quiet mode enabled for overnight running
Talk to the neighbours first
A two-minute conversation before installation prevents most disputes. People object to surprises far more than to equipment.
If a neighbour has concerns, we are happy for you to share the manufacturer's noise data and the proposed position.
Frequently asked questions
- Can I box the unit in to hide the noise?
- Only with a screen that allows free airflow. Sealing a condenser into a box damages performance and can make noise worse.
- Are cheap units noisier?
- Generally yes. Sound data is published, and the difference between budget and premium ranges is audible.