Multiple air source heat pumps running in the same street to heat people’s houses would not noticeably increase background noise, even in worst-case scenarios, modelling in a new report finds.

The average heat pump produces a low hum that is approximately about as loud as a refrigerator, and comparable to the average boiler. The maximum permissible noise level for a single heat pump, set by the standards body MCS, is 42 decibels (dB), as measured at the nearest neighbouring property. A quiet library is around 40 dB. Despite this, a Government review in January noted that in some planning applications concerns had been raised about cumulative noise from multiple heat pump installations.

Nesta, the innovation charity, commissioned consultancy Apex Acoustics to report on the noise impact from multiple air source heat pumps being installed in terraced and semi-detached housing areas.

The modelling finds multiple air source heat pumps do not typically generate noise levels that would be distinguishable from that of a nearby single air source heat pump installed within MCS guidelines. This is the case even if the heat pumps generated their top noise levels at full power all at the same time in a neighbourhood with the densest possible terraced housing.

Katy King, deputy director of sustainable future at Nesta, said:

“Heat pumps are the most efficient way to reduce carbon emissions in people’s homes, so it’s reassuring that having one installed in every house in a neighbourhood makes almost no difference to noise levels.

“Every year manufacturers are producing quieter heat pump models and a properly installed unit is already only as audible as the hum of a fridge or the sound of a gas boiler. It’s concerning that some planning applications have factored in unevidenced worry about noise when it comes to heat pump installations. This study shows that even with all the worst-case factors in place, there is little risk of people being able to notice the sounds of multiple heat pumps running alongside each other to heat people’s houses.”

Notes to editors

1. For more information on the analysis or to speak to one of the experts involved, please contact Kieran Lowe, Media Lead, on 020 7438 2576 or [email protected]. Spokespeople are available for broadcast interviews.