Appeal 3366762

The appeal is dismissed.

The Town and Country Planning (General Permitted Development) (England) (Amendment) Order 2025 (‘the Amendment Order’) came into force on 29 May

It includes alterations to Schedule 2, Part 14 Class G, which concerns the installation or alteration of air source heat pumps (‘ASHP’) on domestic properties. It sets out that the installation of a microgeneration air source heat pump on a dwellinghouse is permitted development provided it complies with the Microgeneration Certification Scheme Planning Standards (‘the MCS’), and it accords with various other limitations and conditions. The MCS were updated on 14 April 2025.

Having regard to both principal parties’ evidence, and as those changes took place around the time the appeal was submitted, I provided them with an opportunity to comment, and I have considered their representations in my decision.

The main issue is the effect of the proposal on nearby occupiers’ living conditions with regard to noise.

The ASHP would be located at ground floor level on the rear face of the host property, 1 metre at its closest point from the boundary with the neighbouring terraced house at [address] (‘No 4’). I observed that No 4 has patio doors which appear to be a broadly similar distance at their closest point from the boundary fence as the proposed ASHP, and which lead straight onto that property’s small private outdoor amenity space, with a first floor window above.

In an email dated 12 May 2025 the Council’s Environmental Health Officer refers to a [name] from the Institute of Acoustics (‘BN’), and states that, as the proposed ASHP would exceed the MCS limit of 42dB(A) at the assessment position, there is the potential for noise from it to affect nearby dwellings. The Council therefore maintains that insufficient information has been provided to demonstrate that the ASHP would not have an unacceptably adverse impact on neighbours’ amenities due to noise.

The appellant states that the scheme was accompanied by a comprehensive noise assessment, and that the MCS 020 [name] demonstrates that the adjusted maximum noise level from the ASHP at the assessment position would be 43.59dB(A), and that this maximum noise level would only be for about 10% of its operating time. The Planning Statement from [name] maintains that a smaller heat pump would not provide enough heat for this property

He says that demanding further costly acoustic assessments or mitigation measures for a minor exceedance of levels permitted by The Town and Country Planning (General Permitted Development) (England) Order 2015 (‘GPDO’) would be disproportionate and unreasonable for this small scale domestic scheme; and that it would be counterproductive to policies which seek to promote the transition to sustainable heating solutions, and it would discourage other applicants from installing an ASHP on their property. He continues that no such assessment was requested by the Council at application stage.

For my part, I note that, as a result of the Amendment Order, and with reference to the latest MCS, the maximum noise limit for an ASHP under Schedule 2, Part 14 Class G of the GPDO has been reduced from 42dB(A) to 37dB(A) at the assessment position. On that basis, the proposed ASHP still requires planning permission, but it exceeds the threshold for permitted development by a greater margin than at the time the application was determined.

The immediate context of the site comprises domestic properties and their rear gardens. [name] experienced on my visit, and as partially evidenced by the submitted [address] Noise maps, whilst this is a reasonably quiet residential area, there is some background noise, partly from rail and road traffic, including from the nearby A1179.

The BN advises that adherence to the MCS alone may not avoid the creation of significant adverse impacts from noise, as average sound levels do not take account of an ASHP’s individual and distinctive noise characteristics, such as audible hums, buzzes, or clunks. It states that where planning permission is required, a noise assessment in accordance with BS4142 should therefore be undertaken by a suitably qualified acoustician or an environmental health practitioner. It continues that the assessment should be proportionate, taking into account local circumstances, and the nature of the particular installation.

In this case, the appellant states that there would be a barely perceptible difference in noise compared to the level permitted by the GPDO. However, it is clear that the ASHP’s noise levels would not comply with the MCS, and having regard to the stance in the BN as set out above, and in the absence of a more detailed noise assessment by a suitably qualified acoustician, I cannot be certain that it would not have particular noise characteristics that could harmfully impact neighbouring occupiers’ amenities, nor can I properly assess whether any mitigation measures would be required.

Whilst the appellant maintains that the ‘blanket refusal’ of any ASHP which exceeds the thresholds in the GPDO is unreasonable, it is clear to me that where planning permission is required the onus is on the applicant to provide evidence that the amenities of nearby residential occupiers would not be harmfully impacted. For the above reasons, and based on the evidence before me, I cannot be sure that this ASHP would not result in a harmfully adverse impact on adjacent occupiers’ living conditions due to noise.

The scheme would therefore be contrary to Policy LP17 part c of the Peterborough Local Plan 2016 to 2036 (2019) (‘PLP’), and to paragraphs 187 part e) and 198 of the National Planning Policy Framework 2024 (‘Framework’).

In favour of the proposal the appellant notes that a typical ASHP can reduce a house’s carbon emissions by 75%. The scheme would thus contribute to the objectives in the Council’s Climate Change Action Plan (2023) of ensuring that Peterborough becomes a net zero carbon city. It also finds support from paragraphs 161 and 165 of the Framework which seek an increase in the use and supply of renewable and low carbon energy, and a transition to net zero by 2050.

I recognise the contribution that small-scale projects such as this make to cutting greenhouse gas emissions. I have given significant weight to the proposed low carbon heating improvements to this building, in accordance with Framework paragraphs 167 and 168.

However, whilst PLP Policy LP31 encourages the provision of site-based renewable energy infrastructure, as the scheme has not fully taken residential amenity into account, or identified any reasonably required measures for mitigation, it has not been demonstrated that its benefits would outweigh the harm that it could cause. Consequently, it does not comply with that policy.

[name] have found that the scheme would fail to comply with development plan policies, and as it has not been demonstrated that compliance with those policies is not feasible or viable, it would also conflict with Framework paragraph 166.

For the above reasons, and having regard to all other matters raised, the appeal is dismissed.