What Changed
On 10 December 2025, MCS published a standards update describing the first step toward bringing air-to-air heat pumps into the scheme. That is a real standards signal, but the official pages still stop short of promising a final go-live date for full installer certification.
This represents a big expansion of the MCS certification scheme, bringing air-to-air heat pumps into the formal framework alongside air-to-water and ground-source systems.
- Official standards update: MCS announced a heat pump standards update as a first step toward bringing air-to-air systems into MCS. Source (MCS)
- Product-standard move: MCS also updated the heat-pump product standard on 28 April 2025, widening scope to include air-to-air and hybrid heat pumps.
- Grant-policy move: GOV.UK now lists £2,500 towards an air-to-air heat pump under the Boiler Upgrade Scheme.
Why this matters: the scheme, product standard, and grant guidance are now pointing in the same direction. The practical question is no longer whether air-to-air is being taken seriously. It is how quickly installers can get their survey, siting, and compliance evidence ready for a live grant route.
Why Installers Care
Air-to-air systems can expand your install offering, but they also introduce different evidence questions. Where air-to-water often hinges on emitter upgrades and pipework, air-to-air must demonstrate that the system is matched to room usage and heat demand.
If you are working in tighter properties or mixed-use spaces, the evidence trail becomes even more important. Room use patterns, zoning intent, and the relationship between indoor units and outdoor placement all need to be defensible if questions arise later.
That means installers need to protect against the same two risks that show up across MCS work:
- Survey evidence requirements: if the evidence does not match the design, the job can be delayed or challenged in compliance checks.
- Callbacks and rework risk: missing room data or unclear siting details can trigger return visits just to fill gaps.
- Customer expectations: air-to-air is often sold on comfort and speed; evidence gaps translate into delays that customers notice.
Installers who capture consistent room-by-room evidence early can add air-to-air jobs without increasing admin overhead, and keep MCS audits smooth when the standards land.
Think of the survey report as insurance: if standards tighten, a thorough report can still pass because it already contains the information a reviewer is likely to request.
It also reduces internal friction. When your designers and installers trust the survey data, you can move from quote to install without debates about missing room context.
What to Capture on Site
Until the standard is fully implemented, the safest approach is to capture evidence that proves the system was specified for the actual building and room conditions.
That means capturing both the physical layout and the assumptions behind zoning. A quick set of wide shots is rarely enough when the decision hinges on airflow, door positions, or internal obstructions.
- Room-by-room photos: room layout, heat emitter presence, glazing, and any obstructions to airflow.
- Unit siting evidence: indoor and outdoor unit positions, clearances, and access routes for maintenance.
- Electrical supply details: consumer unit position, spare capacity, and visible cable routes.
- Fabric and insulation context: loft insulation depth, construction type, and obvious thermal weak points.
- Existing heating context: current system type and controls, especially where zoning or occupancy patterns are relevant.
- Documents on the day: EPC (if available), proof of insulation, and any previous survey reports.
RdSAP evidence documents should be photographed on the day when applicable. That removes the most common source of evidence gaps later in the process.
If you need to model or justify room loads later, these photos and notes help maintain alignment with the original survey, even if the customer delays the install decision.
Evidence Requirements
For air-to-air heat pump installations, survey evidence typically includes:
- Room-by-room documentation: photos and measurements for each room
- Unit siting evidence: indoor and outdoor unit positions, clearances, access routes
- Electrical supply details: consumer unit position, spare capacity, cable routes
- Fabric and insulation context: loft insulation depth, construction type, thermal weak points
- Existing heating context: current system type and controls, especially where zoning or occupancy patterns are relevant
Complete evidence capture helps ensure smooth compliance checks when MCS certification becomes available for air-to-air systems.
What has actually been published so far
The safest reading is the boring one: stick to the dates and documents MCS and Ofgem have actually published, and do not invent a launch date they have not promised yet.
What is already on record:
- 28 April 2025: MCS 007 v7.0 broadened scope to include air-to-air and hybrid heat pumps.
- 10 December 2025: MCS published the first-step standards update article for bringing air-to-air into the scheme.
- 28 April 2026: the approved BUS grant categories and values became effective, including a £2,500 air-to-air heat pump grant.
- 5 May 2026: GOV.UK updated the approved grant values notice.
That is enough to justify preparation work now. For the live grant position, use the £2,500 air-to-air grant update.
Official reference points
MCS described the December 2025 update as the first step toward implementing air-to-air into the scheme. That is the clearest direct scheme statement so far.
MCS 007 v7.0 broadened scope to include air-to-air heat pumps and hybrid heat pumps. That matters because the product side moved before the full installer route was finished.
GOV.UK now lists the £2,500 air-to-air BUS grant. That makes survey readiness commercially relevant now, even while standards work continues.