MCS published an update on 13 April 2026 on its progress towards bringing air-to-air heat pump systems into its certification scheme, covering competency requirements for installers, changes to standards and the next steps for certification bodies1.
The body said a business's Technical Supervisor assigned to an air-to-air heat pump installation must hold competence in Refrigeration, Air Conditioning and Heat Pumps (RACHP) at Level 3 or above1. MCS said the requirement was informed by engagement with certification bodies, trade associations, manufacturers and awarding organisations, and that refrigerant gases used in air-to-air systems carry higher risks of toxicity, flammability and high pressure than a hydronic system, with refrigeration systems working at much higher pressures1. It said RAC level 3 S/NVQ qualifications are recognised UK-wide and by all industry organisations in the refrigeration and air conditioning sector as a suitable level of competence, and that the requirement aligns with other MCS certified technologies1. Some existing MCS installation businesses may already hold these qualifications in their teams, while others will need to bring them in through training, hiring or subcontracting1.
Updated MCS Standards were published in December, and MCS listed the changes now in place1:
| Document | Change |
|---|---|
| MCS 007: Heat Pump Product Standard | Seasonal Coefficient of Performance data needed to raise a certificate must be taken from the ErP label; new requirements for minimum energy efficiency, maximum sound power level and water heating energy efficiency for air-to-air heat pump systems; updated test conditions suitable for air-to-air heat pumps1 |
| MCS 031: Heat Pump Pre-Sale Information and Performance Calculation | Separated into 031 a) for air-to-water heat pumps and 031 b) for air-to-air heat pumps, with a new methodology and tool1 |
| MIS 3005-D: Heat Pump Design Standard | New section added to clause 3.4.3 in the redeveloped installer Scheme version covering system design of air-to-air heat pumps; further changes to MIS 3005-D and MIS 3005-I to make clear the distinction between air-to-water and air-to-air heat pump systems1 |
MCS said core redeveloped Scheme documents, including the Installer Operating Requirements and Conformity Assessment Guidelines, have also been updated and will be available to view on its website in the coming weeks1. It said the updates primarily focus on revisions to scope sections, providing greater clarity on the types of heat pumps covered, with air-to-air and air-to-water systems clearly distinguished1.
"MCS has made significant progress toward implementing air-to-air heat pump systems into the Scheme"
Why it matters for households
Air-to-air heat pumps provide cooling as well as heating, and MCS says they can be more accessible for households living in flats or smaller homes1. The certification work matters because MCS certification is the route by which installations are recognised under the Boiler Upgrade Scheme, and MCS states that air-to-air systems will soon be eligible for funding under the BUS1. Until certification bodies hold UKAS accreditation to offer air-to-air heat pump certification, and until products appear in the MCS Product Directory, households cannot obtain an MCS certified air-to-air installation1. The competency requirement also means the pool of businesses able to carry out certified work depends on how many already hold RACHP Level 3 competence or bring it in1. For a home, an air-to-air system is a different proposition from a wet system: it heats air directly rather than water, and the standards changes now separate the two categories explicitly1. The heat pump standards and certification route is the framework within which any of this work is certified.
What happens next
MCS said it is working with installer certification bodies to support them through gaining UKAS accreditation to offer air-to-air heat pump certification, including ensuring they have the correct competencies in their teams to assess installers delivering these systems, with timescales varying depending on certification body preparation, readiness and UKAS resources1. It is also working with product certification bodies to ensure a pipeline of air-to-air heat pump products are available in the MCS Product Directory and ready for use in MCS certified installations1. MCS said it will continue to provide updates on progress towards fully implementing air-to-air heat pump systems into the Scheme1. No dates for completion of accreditation or for BUS eligibility have been reported1.
Sources1 cited
- Update on the implementation of air-to-air heat pumps into MCS - MCS, mcscertified.com