The United Kingdom Accreditation Service has approved updates to the redeveloped MCS Installer scheme to incorporate air-to-air heat pumps, MCS announced on 8 September 2026. The approval means MCS can move to the next stage of bringing the technology fully into the scope of the scheme1.
Three scheme documents were updated: the Installer Operating Requirement to Version 2.0, the MCS Customer Commitment to Version 1.1, and the Conformity Assessment Guidelines to Version 2.01. MCS said a number of MCS certified air-to-air heat pump products are now available, ready for use in certified installations once the technology is fully in scope1.
"UKAS (United Kingdom Accreditation Service) has approved updates to the redeveloped Installer scheme to incorporate air-to-air heat pumps."
The next stage is supporting MCS installer certification bodies in progressing towards UKAS accreditation, so they can offer air-to-air heat pump certification to installers1. NAPIT and Certsure (NICEIC) are the first two certification bodies that have expressed interest in applying for accreditation, and MCS said it is working with both organisations and UKAS to expedite the process. MCS stated that the timeline is outside its direct control1.
Each certification body will be required to demonstrate its ability to deliver air-to-air heat pump certification. As part of that assessment, each body will select an installer who has completed an air-to-air heat pump installation, and that installation will be used to demonstrate the body's ability to assess and MCS certify the installer1.
Installers will be able to apply for MCS certification for air-to-air heat pumps once certification bodies have gained accreditation through UKAS1. The Technical Supervisor appointed by an installation business for an air-to-air heat pump installation must hold competence in Refrigeration, Air Conditioning and Heat Pumps (RACHP) at Level 3 or above1. MCS is also developing guidance for installers on communicating the considerations and benefits of a certified installation, which it says will be available by the time the first installers are certified. That guidance covers the requirement that systems delivered under MCS must be optimised to deliver 100% of the property's heating requirements1.
Why it matters for households
MCS certification is the route by which a domestic renewable installation is recognised as meeting scheme standards, and it underpins access to some government support. Air-to-air heat pumps, which heat and cool air rather than water, have sat outside the MCS installer scheme, so a household choosing one could not use an MCS certified installer for that technology. The approval moves the scheme towards closing that gap, but it does not close it yet: no installer can hold MCS certification for air-to-air heat pumps until certification bodies are accredited1.
For a home's energy independence, the practical effect is about who can certify the work and on what terms. The RACHP Level 3 requirement for the Technical Supervisor sets a competence floor for the trade1. The 100% heating requirement is a design condition: a certified system must be specified to meet the property's full heating load, rather than part of it1. Air-to-air heat pumps remain outside the Boiler Upgrade Scheme grant, and nothing in the announcement changes that.
What happens next
MCS will work with certification bodies that have shown intent to add air-to-air to their scope, and will provide progress updates as the process moves forward1. No date has been given for when accreditation will be granted or when installers will first be able to apply for certification; MCS said the timeline is outside its direct control1.
Sources1 cited
- Implementation of air-to-air heat pumps into MCS enters next phase - MCS, mcscertified.com