Last reviewed: 2 April 2026. This page reflects Ofgem’s draft BUS installer guidance v5 published in March 2026. The changes discussed here are framed around applications properly made on or after 28 April 2026, so installers should still check the live guidance before relying on the detail.
The April 2026 BUS update matters because it changes an application-stage rule 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.
What actually changes on 28 April 2026
| Change | What the source says | What it means in practice |
|---|---|---|
| EPC requirement | The draft installer guidance says retrofit BUS applications can proceed without a valid EPC from 28 April 2026. | Quoting teams cannot assume an EPC will fill the background-data gap. The survey needs to stand on its own. |
| Air-to-air eligibility | The Ofgem summary of updates says air-to-air heat pumps become eligible in residential properties, with a separate grant route. | Teams need clearer room-use, controls, condensate, and unit-location notes before quoting a system new to their workflow. |
| 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. |
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.
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 document is being loosened. What has changed is where the burden sits: more of it now sits with the survey pack and the judgement applied when the quote is built.
Sources
For the narrower EPC question within this update, read the EPC companion guide.