UK Ministers have been told, that heat pumps are too loud to be installed in millions of homes under the UK Government’s noise guidelines.

The UK Government aims to install 600,000 heat pumps a year by 2028 to hit net zero targets, but a report seen by The Daily Telegraph, sound specialists warn uptake could be limited.

The study reveals that most heat pumps are too loud for many homes in built-up areas, such a terraced houses and flats, because they would break noise limits set for home-owners 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 installed in urban areas.

The findings, produced by a group of noise experts, have been sent to the UK Government to contribute to a review into heat pump noise being run by the Department of Energy Security and Net Zero (Desnz). Air source heat pumps, which are positioned outstand 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 UK 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 to qualify for the grant, 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 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 the top heat pumps from the five main manufacturers, not one device would meet MCS standards on noise unless the unit was at least four metres away.

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

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