If this relates to a live job, our heat pump survey, ASHP survey, and heat loss survey pages explain what we capture before design and grant paperwork move forward.
The April 2026 BUS update matters because it changes application-stage checks that many installers used as a rough screen during quoting. It does not remove the need for proper site evidence. If anything, it makes the survey more important because a missing EPC can no longer do part of the background work for you.
For the newest grant-specific page, read the £2,500 air-to-air heat pump grant update.
If you are looking for the live off-grid grant story rather than the April ruleset change, use the BUS £9,000 oil and LPG grant update. That page tracks what is publicly confirmed, what is being reported, and what is not published officially yet.
What this means from 28 April 2026
| Change | What the source says | What it means on site |
|---|---|---|
| EPC requirement | BUS v5 changes the EPC position for retrofit applications made on or after the change point. | Quoting teams cannot assume an EPC will fill the background-data gap. The survey needs to stand on its own. |
| Air-to-air eligibility | Ofgem’s update brings an air-to-air route into scope for residential properties, subject to the scheme rules. | Teams need clearer room-use, controls, condensate, and unit-location notes before quoting a system that will be new to many customers. |
| Exhaust-air eligibility | The update also sets out where exhaust-air systems may qualify under the air-to-water route. | Eligibility becomes broader, but the survey still has to capture the system type and distribution setup accurately. |
| Supplementary heating | BUS v5 gives installers more to check around retained or supplementary heating arrangements. | The survey should record existing heat sources, distribution, controls, and any retained appliances clearly enough for the installer to assess eligibility. |
What does not change
- MCS design and installation obligations still sit outside the BUS application form itself.
- Heat loss inputs still need to be defensible.
- Emitter, electrics, cylinder, access, and outdoor-unit decisions still need site evidence.
- The accredited installer still carries responsibility for the application and scheme compliance.
Supplementary heating and existing systems
One of the most practical BUS v5 issues is not the headline grant number. It is what the property already has. If a home has an existing boiler, stove, electric heater, secondary heat source, unusual controls, or mixed distribution, the installer needs a clean record before promising a grant route or building a quote around it.
A good air source heat pump survey should therefore record the current heating setup in plain language: what is present, what is retained, what is being replaced, how hot water is handled, what the emitters are, and whether the proposed system is expected to serve the full space heating load. That evidence is separate from the design calculation, but it affects whether the quote and BUS application make sense.
- Photograph the existing boiler, cylinder, controls, emitters, and any obvious secondary heat source.
- Record whether supplementary heating is being removed, retained, or outside the proposed scope.
- Capture enough notes for the installer to check the BUS rules before submitting the application.
- Keep the evidence with the job record so office, design, and compliance teams are not relying on memory.
What the survey should now be able to answer without leaning on an EPC
| Question before quote | Evidence worth capturing on site |
|---|---|
| Can the property support the proposed heat source? | Fabric notes, glazing notes, usable plant space, emitter picture, and any obvious route or clearance issues. |
| Is the electrical side straightforward? | Consumer unit photos, supply details, spare ways, meter location, and anything likely to trigger an upgrade conversation. |
| Can the designer size confidently? | Room dimensions, emitter information, construction notes, and the constraints that affect assumptions. |
| Is the chosen grant route even plausible? | Clear notes on existing heating, distribution type, property use, and the system category being proposed. |
What to ask when there is no valid EPC
- What evidence will we rely on for the building fabric and heating baseline?
- Do we have enough photos and notes to justify the heat loss assumptions later?
- If the customer has an expired EPC, utility bill, or previous assessment, has that been captured and filed clearly?
- Can the office explain the quote without promising that the grant process itself has become risk-free?
A practical survey checklist for BUS-era quoting
- Record the current heating and hot-water setup clearly.
- Capture room and emitter information where it will affect design.
- Photograph electrics properly rather than treating them as an afterthought.
- Note access, routes, and outdoor-unit constraints in plain language.
- Keep supporting documents together if the customer already has them.
The commercial risk has not vanished just because one application-stage rule is being loosened. What has changed is where the burden sits: more of it now sits with the survey report, the heat loss assumptions, and the judgement applied when the quote is built.
Official reference points
Check the current Ofgem BUS installer guidance before submitting. This page is an installer-facing summary, not a substitute for the scheme rules.
The v5 change point is applications properly made on or after 28 April 2026. That date is the practical handover point teams should use when checking evidence.
The practical changes sit around EPC position, air-to-air eligibility, retained or supplementary heating, and clearer evidence before application.
Sources
For the EPC part of this update, read the EPC companion guide.