Guide · Installation
Heat pump noise and UK regulations
What MCS 020 actually allows, what your neighbours will hear, and how to avoid a planning headache.
UK heat pumps must pass an MCS 020 noise assessment that caps sound at 42 dB(A) at the nearest neighbouring window. Modern units run at 40–55 dB at 1 metre. Comply and your install is permitted development; fail and you need a full planning application.
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What MCS 020 measures
MCS 020 is a desk-based calculation: take the manufacturer's sound power figure, factor distance, building reflections and barriers, and check the dB(A) at the assessment point. Your installer does this — you don't need a noise consultant for a standard install.
Siting that passes first time
- Keep the unit 1m+ from any boundary fence or wall.
- Avoid pointing the fan grille directly at a neighbour's window.
- Use an acoustic enclosure on tight urban plots — adds 5–10 dB of attenuation for £400–£900.
- Pick a low-noise model. Daikin EBLA, Mitsubishi Ecodan QUHZ and Vaillant aroTHERM plus all sit under 50 dB at 1 m.
When permitted development won't cover you
Conservation areas, listed buildings, and flats above ground floor always need full planning. Welsh permitted development rules are stricter (3m boundary distance). In Scotland, separate Class 6F permitted development rules apply.
Frequently asked questions
- How loud is a typical heat pump?
- Modern air source heat pumps run at 40–55 dB(A) at 1 metre — quieter than a fridge at close range and well below conversational speech (60 dB). At your neighbour's nearest window, MCS 020 caps the noise at 42 dB(A).
- Do I need planning permission for a heat pump?
- Most installs qualify as permitted development if MCS 020 noise assessment passes and the unit is sited 1m+ from boundaries (England). Conservation areas and listed buildings require full planning permission.
- MCS Certified — Installer certification scheme required for grant eligibility.
- Energy Saving Trust — Heat pump efficiency, running cost and SCOP benchmarks (UK).
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