Despite the government's aim to install 600,000 heat pumps annually by 2028 to achieve zero emissions, experts warn that their deployment may be restricted.
Research indicates that the majority of heat pumps exceed noise limits set for homeowners in densely populated areas such as townhouses and apartments. This breach of noise limits could pose challenges for homeowners seeking to install heat pumps without construction permits and relying on government grants.
Local authorities are also expected to face a surge in noise complaints as eco-friendly devices become more prevalent in urban areas. The findings from noise experts, submitted to the government, contribute to the investigation into heat pump noise conducted by the Department of Energy Security and Net Zero (Desnz).
Air-source heat pumps, situated outside homes, can generate a constant low-level noise ranging from 40 to 60 decibels, similar to the noise level produced by a refrigerator or dishwasher. They typically operate continuously throughout the winter.
While the government encourages homeowners to install heat pumps by offering up to £7,500 in cost coverage through the Boiler Upgrade Scheme (BUS), installations must adhere to Microgeneration Certification Scheme (MCS) rules, including noise level standards. This means heat pumps should not produce noise louder than 42 decibels within one meter of a neighbor's door or window.
However, a report reveals that none of the top five heat pump models from major manufacturers meet MCS noise standards unless placed at least 4 meters away. The authors caution that without MCS compliance, BUS grants may be unavailable, potentially leading to a significant reduction in heat pump usage in England and Wales.
Heat pump installations must also meet MCS standards to qualify for permitted development without construction permits. The report, prepared by noise consulting firms Apex Acoustics, Sustainable Acoustics, and ANV Measurement Systems, highlights concerns about the difficulty households face in interpreting noise level information provided by manufacturers.
Experts worry that installers may not always offer quieter models, limiting choices to products from a single manufacturer. Ministers intend to outlaw new gas boilers by 2035 to achieve zero emissions, with a ban on gas boilers in new homes from 2025.
The report suggests that planning departments often focus only on visual aspects, and Welsh local authorities anticipate a "sharp increase" in noise complaints if the UK government's deployment goals are met.
To meet noise standards and secure grant funding, some homeowners may need to build a sound barrier, potentially costing up to £5,000, according to Jack Harvey-Clark from Apex Acoustics. However, even with soundproofing, it may not be sufficient to reduce noise to an acceptable level. An alternative could be the more expensive split-system, where part of the heat pump is built inside the home.