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Update to MCS 020 a) & implementation guidance

23 April 2025

Installer doing wiring on heat pump.

On the 20 March 2025, MCS published an update to ‘MCS Planning Standards for Permitted Development Installations of Wind Turbines and Air Source Heat Pumps on Domestic Premises’ (MCS 020), which introduced splitting the Standard into two: one for air source heat pumps (MCS 020 a)) and one for small wind turbines (MCS 020 b)).

Following this publication, there has been a further update to MCS 020 a) – Air Source Heat Pump Sound Calculation.

MCS 020 a) v1 has been updated to MCS 020 a) v1.1. This update includes the removal of the date for mandatory compliance, which will now be dictated by the upcoming changes to Permitted Development Rights (PDR) as determined by UK Government. The date for changes to PDR has not yet been published.

We have also corrected a typo in the barrier attenuation table.

The upcoming changes to PDR are expected to be announced at the end of Spring by the Ministry of Housing Communities and Local Government (MHCLG).

Once the Town and Country Planning (General Permitted Development) (England) Order has been updated, it will specifically refer to MCS 020 a) and will become the only way of complying with this regulation.

Until Permitted Development Rights change only MCS 020 is valid and can be used.

Once PDR changes, MCS 020 will no longer be a valid means of demonstrating compliance for air source heat pump installations in England. Only MCS 020 a) will apply.

For installations in Scotland, Wales and Northern Ireland you should continue to use MCS 020 as their Permitted Development Rights aren’t yet set to change.

The upcoming changes to PDR aim to support the rollout of air-to-air heat pumps that also provide cooling in England. A cooling function has always been allowed under MCS, although it must be designed and optimised for heating as per The Heat Pump Standard (Design) clause 1.8 MIS 3005-D V2.0.

Air-to-air heat pumps that provide cooling currently aren’t eligible for funding under the Boiler Upgrade Scheme. The decision to broaden the scope of technologies is decided by the Department for Energy Security and Net Zero (DESNZ).

MCS will share a further update once the upcoming change to PDR have been implemented by the UK Government.

MCS 020 a) v1.1

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View MCS 020 a) v1.1 here.