Decarbonising our home heating is essential to hitting net zero, but the UK is 90% short of its annual target for installing heat pumps, by far the best option for low-carbon heating. Only 60,000 were installed last year, though we need to hit 600,000 annual installations by 2028.

One of the biggest obstacles to progress are our outdated planning laws.

Unlike a gas boiler, heat pumps are installed outside homes and so are often subject to a host of overly restrictive rules. Octopus Energy says 27% of their customers wanting to install heat pumps have been told to apply for planning permission.

There’s already vigorous political debate about the adverse effect of Britain’s planning system on housing and growth, but it’s also the case that it’s harming sustainability too.

The government is currently consulting on reforming these conditions in England, and we spoke to homeowners, installers, councils and policymakers before submitting our response.

We think there are four changes that everyone interested in boosting heat pump adoption should be demanding before the consultation closes on April 9th, because it really shouldn’t be as complicated as it is.

Householders can be drawn into a complex and lengthy planning process. Councils often require sound assessments (costing around £1,000) and expensive architectural drawings. The more heat pump installations we can remove from the planning process the better, freeing up householder, installer and council time and reducing costs for everyone. The government’s proposed changes to permitted development rights will help the vast majority of consumers to install a heat pump without going through the formal planning process.

Current noise regulations restrict heat pump noise to a maximum of 42dB within 1-metre of a neighbour’s windows. However, as the push for more heat pump installations intensifies, some are worried this limit is too lax and could lead to complaints as the technology becomes more widespread.

While tightening noise limits is an option, considering the low incidence of noise complaints to date, we think that would be overly cautious and unnecessary.

Although some have proposed variable noise limits depending on place and time, for example in rural villages with low ambient noise, we think that would be difficult to implement in practice and hamper take-up in areas that are currently leading the heat pump transition.

Though we think that the way MCS currently calculates whether a heat pump is complying with the rules could be improved, on balance, we think that the existing noise limit of 42dB is set at a reasonable level.

Providing that heat pump installations adhere to noise limitations, relaxing the number of units and size restrictions could accelerate heat pump adoption so we support removing current controls - as long as the rules on noise limits are kept in place (as the government is recommending).

Existing restrictions on the size of heat pumps that can be installed under permitted development (i.e. without planning permission) serve as a barrier to innovation in noise reduction techniques, and the development of quieter, more efficient heat pump models. For example, larger heat pumps can be made quieter due to the greater sound insulation possible inside a larger box.

Permitting multiple installations per building could help address the heating needs, emission targets and energy efficiency of larger homes, particularly in rural areas, but the limitations on the number of heat pump units that can be installed per dwelling are making it more difficult for some detached properties, as well as blocks of flats, to decarbonise their homes with ease.

The 1-metre rule, while initially intended to mitigate noise concerns, has proven to be an overly restrictive proxy measure for noise. Instead of restricting where a heat pump can be installed, the focus should be on addressing noise concerns by ensuring that heat pump installations comply with the 42dB limit.

We’re urging everyone to submit a response to the consultation, encouraging the government to reform the current planning system in a way that makes getting a heat pump easier, but that also ensures environmental and communal safeguards (such as noise limits) are kept.

Please get in contact with Codrina Cretu if you are also planning to respond to the consultation and would like to discuss any of the issues before it closes next month.