Heat pumps ‘too noisy’ for millions of British homes, Government told

Heat pumps are too loud to be installed in millions of homes under the Government’s noise guidelines, ministers have been told.

The Government wants to install 600,000 heat pumps a year by 2028 to hit net zero targets, but a report by sound specialists warns uptake could be limited.

The study reveals that most heat pumps are too loud for many homes in built-up areas, such as terraced houses and flats, because they would break noise limits set for homeowners who want to install one without planning permission and with a government grant.

Local authorities are also braced for a rise in noise complaints as more of the green appliances are installed in urban areas, the report seen by The Telegraph reveals.

The findings, which were produced by a group of noise experts, have been sent to the Government to contribute to a review into heat pump noise being run by the Department for Energy Security and Net Zero (Desnz).

Air source heat pumps, which are positioned outside a home, can produce a low constant hum of between 40 and 60 decibels which is similar to the level of noise made by a fridge or dishwasher. They will typically run continuously throughout winter.

The Government is encouraging homeowners to install heat pumps by offering up to £7,500 towards the cost under the Boiler Upgrade Scheme (BUS). The grant was last month increased from £5,000 after fewer than 10,000 of an available 30,000 vouchers were redeemed in the first year.

But in order to qualify for the government money, heat pump installations must comply with regulations set out by the Microgeneration Certification Scheme (MCS) – including a minimum level of noise disturbance to neighbours. It means a heat pump must not generate a noise louder than 42 decibels within one metre of a neighbour’s door or window.

Yet the report, which was presented to the Institute of Acoustics at a conference, found that of the top heat pumps from the five main manufacturers, not one device would meet MCS standards on noise unless the unit was at least 4m away. 

The authors warned: “Without the MCS there is no BUS grant and, therefore, a likely significant reduction in uptake of [heat pumps] across England and Wales.”

Heat pump installations also have to comply with MCS standards to be installed without planning permission as a permitted development.

The report was compiled by experts from the consultancies Apex Acoustics, Sustainable Acoustics and ANV Measurement Systems. Two of the consultancies were commissioned by the Welsh government to provide advice on heat pump noise, and a summary of the report’s findings have also now been sent to Desnz to be added into the UK-wide review.

The researchers examined the heat pump product factsheets of manufacturers covering around 70pc of the market to work out how noisy they would be, and how far they would have to be sited from a neighbouring home to comply with guidelines. It found models designed to provide a higher heat output, or larger homes, would have to be put as far as 10m away.

Peter Rogers, of Sustainable Acoustics, said all terraces, flats and tenement buildings – equivalent to 47pc of Britain’s housing stock – would struggle to install a heat pump under MCS guidelines. He also said some installations in semi-detached homes, which account for 31pc of homes in Britain, could breach guidelines.

He said that information on noise levels was difficult for households to decipher, adding: “Sound emission data is provided by manufacturers for each model, but it varies hugely how easy it is to find and how it’s presented.”

The researchers also raised concerns that installers do not always offer homeowners quieter models as they often only fit heat pumps made by one manufacturer and are limited to one firm’s products.

Ministers aim to outlaw new gas boilers by 2035 in an effort to hit net zero. Gas boilers in new homes are to be banned from 2025.

The report said planning offices had “tended to only concern themselves with visual aspects”, and that Welsh local authorities were expecting “a sharp increase” in noise complaints if UK government rollout targets were met.

To meet noise regulations and receive grant funding, some homeowners would have to build a sound barrier – potentially at a cost of up to £5,000 – said Jack Harvie-Clark, of Apex Acoustics. But even if sound-proofing was installed, it may not be enough to reduce the noise to an acceptable level.

Alternatively, they could opt for a costly split system, where part of the heat pump is built inside the house.

Mr Harvie-Clark added: “At the minute there is very little incentive for manufacturers to develop more sophisticated, quieter, air-source heat pumps.”

The report concluded that “there is clear objective evidence that the sound emissions from [air source heat pumps] have the potential to cause annoyance and give rise to complaints”.

However, it said manufacturers were increasingly making more efficient and quieter products and that heat pumps were needed to reduce the UK’s reliance on fossil fuels.

The MCS estimates that roughly 3,000 heat pumps are currently being installed every month. A shortage of engineers qualified to install heat pumps has compounded the problem.

Bean Beanland, of the industry lobby group the Heat Pump Federation, said that regulation should be overhauled to encourage manufacturers to produce quieter units, adding: “The current system requires the box around the heat pump to be smaller than 0.6 cubic metres. If that stipulation didn’t exist, manufacturers would be able to put in more acoustic attenuation.”

Charlotte Lee, chief executive of trade body the Heat Pump Association, said the industry continued to invest in product development and the number of ultra-quiet heat pumps will inevitably increase.

She said: “Our industry will continue to support the installation of the most appropriate heat pump solution in all situations.“

A Department for Energy Security and Net Zero spokesman said: “These claims fail to recognise that heat pumps have got significantly quieter over the past decade, with ultra-low noise emission models now available.

“Heat pumps can be installed in the overwhelming majority of homes without the need for planning permission or additional acoustic insulation.”

Have you experienced issues with your heat pump installation? Get in touch: money@telegraph.co.uk