MCS has published an updated version of MCS 020
20 March 2025
Further to consultation in January 2024 and the release of our consultation response in November 2024, MCS has published an updated version of MCS 020.
This update was driven by the government’s consultation and subsequent announcement on amendments to existing Permitted Development Rights (PDR) that apply in England to:
- Remove the 1m boundary rule, enabling heat pumps to be installed within 1m of the property boundary.
- Increase the size limit of the heat pump for dwelling houses from 0.6m3 to 1.5m3.
- Double the number of heat pumps permitted, from one to two for detached dwelling houses.
- Support the rollout of air-to-air heat pumps that can also provide a cooling function.
This update aims to simplify compliance and improve clarity for installers. The key changes are as follows:
- MCS will split the MCS 020 standard into two: one for air source heat pumps and one for small wind turbines (there are no changes to the requirements for small wind turbines):
- MCS 020 (a) – Air Source Heat Pumps Sound Calculation
- MCS 020 (b) – Small Wind Turbine Sound Calculation
- MCS will hold the A-weighted sound power level for MCS certified products on the MCS Product Directory. This figure is to be determined by manufacturers at the same conditions as the Eco Design Directive and MCS will issue guidance to clarify what those conditions are.
- MCS has clarified:
- What can and cannot be considered a solid barrier.
- How to determine the assessment position.
- What can and cannot be considered a reflective surface.
- The definition of a habitable room.
- MCS will introduce a methodology for including up to two air source heat pumps in the MCS 020 (a) sound calculation.
- MCS will provide installers with options for completing the sound calculation which will include the current paper-based method and an Excel tool.
- MCS will include in the Excel tool the capability of completing the sound calculation for up to four air source heat pumps to benefit those installing under full Planning Permission.
- Working with DESNZ and other industry stakeholders, MCS will develop a guidance document for installers on installation noise mitigation measures for air source heat pumps.
- Compliance with MCS 020 a) under PDR will apply irrespective of whether it’s an MCS certified installation or not.
Compliance with this update is mandatory for installers seeking to install air source heat pumps under Permitted Development from the date of implementation – 20 September 2025.
To access the Standards and Excel tool, please visit the MCS Standards & Tools Library or click the links below. Any queries should be sent to meetings@mcscertified.com.
View the updated standards here: