Are Heat Pumps Noisy?
Not really. A modern air source heat pump runs at roughly 40 to 60 decibels measured close to the unit, about the level of a fridge hum or steady rainfall. A few metres away it is usually a soft background whoosh, and indoors you rarely hear it at all. Ground source heat pumps are quieter again, because there is no outdoor fan. UK planning rules cap the noise at the neighbour's boundary, so a properly sited unit stays well within limits.
Quick Answer
No, heat pumps are not noisy. A modern air source heat pump produces around 40 to 60 decibels close to the unit, similar to a fridge or light rain, and much less a few metres away. UK permitted development rules require it to stay at or below 42 decibels at the nearest neighbour's window, and ground source units are quieter still.
Guidance as of early 2026, based on UK heat pump practice.
Fact-checked by John Rooney, Solar Energy Editor. Editorial policy
How noisy is an air source heat pump?
The noise comes from the outdoor unit's fan and compressor. Sound output is rated in decibels and drops quickly with distance, so the figure that matters is measured at the neighbour's window, not next to the box. Manufacturers publish a sound power level, and a good installer works out the sound level at the boundary from it. Newer units are noticeably quieter than early models, with several rated among the lowest in their class.
Heat pump noise compared to everyday sounds
| Source | Approx. Sound Level |
|---|---|
| Quiet library | 30 dB |
| Fridge hum | 40 dB |
| Air source heat pump (close to unit) | 40–60 dB |
| Steady rainfall | 50 dB |
| Normal conversation | 60 dB |
| Heat pump at neighbour boundary | Typically under 42 dB |
Because decibels are logarithmic, the level drops sharply over a few metres, which is why a unit that reads 55 dB at the casing can be under 42 dB at a boundary a few metres away.
Worried about noise for you or a neighbour?
An MCS-certified installer runs a noise assessment as part of the quote and sites the unit to stay within limits. Get free quotes near you.
Get a Quote →The UK heat pump noise limit
To install an air source heat pump under permitted development in England, the noise must be at or below 42 decibels measured one metre from the nearest neighbour's habitable room window. Installers use the MCS planning standard (MCS 020) to calculate this from the unit's rated sound power and its position. If a layout cannot meet the limit under permitted development, the option is a planning application rather than a louder unit. See how heat pump installation works.
Heat pumps and neighbours
Most disputes come down to siting, not the heat pump itself. The 42 decibel limit is measured at the nearest neighbour's window, so where the outdoor unit sits matters as much as how loud it is rated. There is no fixed legal distance an air source heat pump must be from a neighbour, but to qualify for permitted development in England the unit must be at least one metre from the property boundary, and it still has to meet the 42 decibel limit at the neighbour's window. In practice a good installer positions it away from boundaries and bedroom windows to keep well inside both rules.
If you are the one installing
Tell neighbours before work starts, share where the unit will go, and ask your installer for the MCS 020 noise calculation in writing. A unit sited thoughtfully and backed by that paperwork rarely causes a problem, and it protects you if anyone queries it later.
If a neighbour's heat pump is too loud
Start by talking to them. Many issues are a loose mounting, a unit that needs anti-vibration feet, or a fan running hard because the system is undersized, all fixable. If that does not resolve it, your council's environmental health team can assess it as a statutory nuisance under the Environmental Protection Act 1990 and require the owner to reduce it. Keep a simple log of when the noise is worst, as that helps any assessment.
Knowing the noise figures in advance heads most of this off. Have an installer run the assessment as part of the quote, and see what installation involves.
How to keep a heat pump quiet
- Choose a low-noise rated model, several are well under the limit.
- Site the outdoor unit away from bedroom windows and boundaries.
- Mount it on anti-vibration feet on a solid, level base.
- Keep clear space around the unit so air flows without strain.
- Size the system correctly so it does not run flat out in the cold.
Heat Pump Noise FAQ
Are heat pumps noisy?
Not really. A modern air source heat pump runs at around 40 to 60 decibels close to the unit, similar to a fridge or steady rain, and much quieter a few metres away. Ground source heat pumps are quieter still because they have no outdoor fan.
How many decibels is an air source heat pump?
Most modern air source heat pumps are rated around 40 to 60 decibels measured close to the outdoor unit. The level drops quickly with distance, so at a neighbour's boundary a few metres away it is typically under 42 decibels.
What is the noise limit for a heat pump in the UK?
To qualify for permitted development in England, an air source heat pump must be at or below 42 decibels measured one metre from the nearest neighbour's habitable room window. Installers calculate this using the MCS 020 planning standard.
Can I hear a heat pump inside the house?
Usually not. The compressor and fan are in the outdoor unit, so indoors a heat pump is generally inaudible. The indoor parts, a hot water cylinder and pump, are about as quiet as a normal central heating system.
Are ground source heat pumps quieter than air source?
Yes. A ground source heat pump has no outdoor fan, with the working parts housed indoors, so it is noticeably quieter than an air source unit and runs at a low, steady hum.
How can I reduce heat pump noise?
Choose a low-noise rated model, site the outdoor unit away from bedroom windows and boundaries, mount it on anti-vibration feet on a solid base, leave clear space around it for airflow, and size the system correctly so it does not run flat out.
How far does an air source heat pump need to be from a neighbour?
There is no fixed legal distance, but to qualify for permitted development in England the outdoor unit must be at least one metre from the property boundary and must stay at or below 42 decibels measured at the nearest neighbour's window. Good installers site it away from boundaries and bedroom windows to meet both comfortably.
What can I do about a noisy heat pump next door?
Talk to the owner first, as many problems are a loose mounting, missing anti-vibration feet, or an undersized unit running hard, all fixable. If it is not resolved, your council's environmental health team can assess it as a statutory nuisance under the Environmental Protection Act 1990 and require the owner to reduce it. A simple log of when the noise is worst helps.
Do I need my neighbour's permission to install a heat pump?
No, you do not need permission, but the install must meet the permitted development rules including the one metre boundary distance and the 42 decibel limit at their window. It is good practice to tell neighbours beforehand, show where the unit will go, and keep the MCS 020 noise calculation in case anyone queries it.
Find a heat pump installer near you
An MCS-certified installer assesses noise and sites the unit to stay within the planning limit.
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Sources
Last updated: July 2026
John Rooney is the founder of Solar Info and has been covering the UK solar energy market since 2023. He researches every battery and inverter brand against manufacturer datasheets, MCS and Ofgem data, and feedback from the MCS-certified installers in our directory before publishing.
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