What is the MCS noise limit for heat pumps?

MCS 020 (Planning Standards) requires that the noise from a heat pump at the nearest noise-sensitive premises (typically the nearest neighbour window) must not exceed the measured background noise level by more than 5 dB(A). This is assessed at the nearest noise-sensitive window, not just the boundary.

How loud is a typical heat pump?

Most modern ASHPs produce 45-60 dB(A) at 1 metre. At full load, a typical 10 kW ASHP produces about 55 dB at 1m. At 3 metres, this drops to approximately 45 dB. At 10 metres, it would be approximately 35 dB — similar to a quiet library. Inverter models are quieter at part load.

How does distance affect heat pump noise?

Sound level reduces by approximately 6 dB for every doubling of distance over hard ground (inverse square law). So a 55 dB source at 1m becomes 49 dB at 2m, 43 dB at 4m, and 37 dB at 8m. Soft ground (grass) provides additional absorption of approximately 1.5 dB per doubling.

Do I need planning permission for heat pump noise?

Heat pumps installed under permitted development rights must comply with MCS 020 noise criteria. If the noise assessment fails, you may need to apply for full planning permission, add acoustic mitigation, choose a quieter unit, or relocate the outdoor unit to a position with greater distance to neighbours.

How can I reduce heat pump noise?

Options include: increasing distance to boundaries (most effective), installing a close-boarded fence (-5 dB) or masonry wall (-10 dB), fitting an acoustic enclosure (-15 dB), using anti-vibration mounts, selecting an inverter model that runs quietly at part load, and applying night-time setback modes.

TradeCalculator

Heat Pump Noise Calculator

Calculate noise levels at property boundaries and neighbouring windows using inverse square law attenuation. Check MCS planning compliance.

Source Noise Level

From manufacturer datasheet

Distance to Boundary

From HP to nearest boundary

Distance to Nearest Window

Neighbour noise-sensitive window

Location Type

Sets background noise level

How We Calculate This

This calculator predicts the noise level from a heat pump at the property boundary and nearest neighbour window, and checks compliance with MCS 020 planning standards.

Noise calculation

Distance attenuation: 20 x log10(distance) — inverse square law
Soft ground: Additional 1.5 dB per doubling of distance
Wall reflection: +3 dB when HP is against a wall
Barriers: Fence -5 dB, wall -10 dB, acoustic enclosure -15 dB
MCS limit: Background noise + 5 dB at nearest sensitive window

Frequently Asked Questions

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Last updated: March 2026

All calculations are estimates. Verify with your supplier.