Heat Pump Noise & Planning Permission - UK 2026 Guide
Most UK homeowners can install a heat pump without planning permission. Here is exactly what the rules say, what the noise limits are, and how to check if your installation will comply.
Key facts
Permitted development: when you don't need planning permission
Since December 2011, installing an air source heat pump is classified as permitted development in England, meaning planning permission is not required, provided all conditions below are met. Wales has equivalent permitted development rights under its own planning regulations.
All conditions must be satisfied:
- The unit does not exceed 1.5 cubic metres in volume.
- It is not installed on a wall or roof that faces a highway.
- The unit is located at least 1 metre from the property boundary.
- The noise level does not exceed 37 dB(A) at the nearest neighbouring window (MCS 020).
- In conservation areas: the unit must not be visible from a highway.
- Only one heat pump may be installed on the property at any time.
The 37 dB noise limit explained
The 37 dB(A) limit in MCS 020 is measured at the nearest neighbouring habitable room window — not at the heat pump itself. This is an important distinction. A heat pump that produces 48 dB(A) at 1 metre can still comply with the 37 dB limit at a neighbour's window 5–10 metres away, because sound reduces with distance (roughly 6 dB per doubling of distance in open conditions).
Noise levels in context
| Sound source | Level |
|---|---|
| Quiet library | 30–40 dB |
| Refrigerator hum at 1 metre | ~40 dB |
| Normal conversation | 50–60 dB |
| MCS 020 legal limit (at neighbour's window) | 37 dB |
| Modern heat pump at 1 metre (unit itself) | 40–55 dB |
| Heat pump at 3 metres | ~32–47 dB |
How the noise calculation works
Your MCS-certified installer must use the official MCS Sound Calculator before installation. The calculation takes four steps:
- Take the manufacturer's published Sound Power Level (LWA) at the design operating point (typically 0°C outdoor, 45°C flow temperature)
- Apply corrections for reflective surfaces within 1 metre of the unit (walls, fences, the house itself)
- Calculate the predicted sound pressure level at the assessment position (1 metre from the neighbour's nearest habitable window)
- Compare against the 37 dB(A) limit
Reflective surfaces increase the noise calculation — a unit in a corner with two walls behind it may be 3–5 dB louder in the calculation than the same unit in open space. An experienced installer will account for this in positioning.
What if my installation doesn't comply?
If the noise calculation shows the installation would exceed 37 dB(A), you have several options:
- Reposition the unit to increase distance from the neighbour's window, or reduce reflective surfaces nearby
- Choose a quieter model — a unit with a lower LWA rating may pass where another doesn't
- Install acoustic barriers (acoustic fencing or enclosures can reduce noise by 5–10 dB in some configurations)
- Apply for planning permission if permitted development conditions cannot be met
Quietest heat pump models for UK homes
Noise levels measured at 1 metre from the unit. All figures from manufacturer data at rated operating conditions.
Frequently asked questions
Do I need planning permission for a heat pump in the UK?
In most cases, no. Air source heat pump installation is considered 'permitted development' in England and Wales, meaning planning permission is not required, provided certain conditions are met. These include: the unit must not exceed 1.5 cubic metres in volume; it must not be installed on a wall or roof facing a highway; it must be at least 1 metre from the property boundary; and the noise level must not exceed 37 dB(A) at the nearest neighbouring habitable room window (MCS 020 standard). Properties in conservation areas have additional restrictions on positioning but are rarely prevented from having a heat pump.
What is the noise limit for a heat pump in the UK?
Under MCS 020 Planning Standards, the sound pressure level from a heat pump must not exceed 37 dB(A) at the nearest neighbouring habitable room window, measured at 1 metre from that window. This is roughly equivalent to leaves rustling in a light breeze. Note: the 37 dB limit is measured at the neighbour's window, not at the heat pump itself. Modern heat pumps produce 40–55 dB at 1 metre from the unit — sound reduces significantly with distance.
How far does a heat pump need to be from the boundary?
To qualify for permitted development (no planning permission required), the outdoor heat pump unit must be at least 1 metre from the property boundary. There is no minimum distance requirement from the main house itself, though positioning is guided by noise calculations and airflow needs. Your installer will calculate the noise impact before confirming positioning.
Can I install a heat pump in a conservation area?
Yes, in most conservation areas. The key restriction is that the unit must not be visible from a highway. In practice, this means positioning at the rear or side of the property — which is standard for most installations regardless of conservation area status. In very rare cases (e.g. certain listed buildings), restrictions may be tighter. Check with your local planning authority if unsure.
How is the heat pump noise compliance checked?
Your MCS-certified installer must carry out a sound level calculation using the manufacturer's published Sound Power Level (LWA) data and the MCS Sound Calculator tool. This accounts for: distance from the unit to the neighbour's window; the number of reflective surfaces within 1 metre; any acoustic barriers; and whether the noise is tonal. The predicted result must be 37 dB(A) or below at the assessment position to comply.
What is the quietest heat pump available in the UK?
The Vaillant aroTHERM plus is the quietest premium heat pump widely available in the UK, with noise levels of 37–43 dB(A) at 1 metre. It carries Quiet Mark certification. The Samsung EHS Mono HT Quiet and Mitsubishi Ecodan 5 kW are also Quiet Mark certified or independently rated as very quiet. In general, smaller-output models (5–8 kW) run quieter than larger units (12–16 kW).
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Important disclaimer
www.heatpumpcompared.co.uk is editorially independent and not affiliated with any heat pump manufacturer or installer. We do not provide heating advice. Prices, specifications, SCOP ratings and grant amounts are correct as of April 2026 but are subject to change. Always commission a professional heat loss survey before purchasing a heat pump system.