Note: This article is based on Ofgem draft BUS V5 guidance published in late March 2026 and expected to apply to applications properly made on or after 28 April 2026. Installers should check the final published guidance before changing customer advice or internal process.
The application got simpler. The survey did not.
Installers will hear the headline and assume one part of the job got easier. It did. Retrofit BUS applications are expected to move ahead without a valid EPC, and the BUS eligibility picture has widened, with air-to-air now in scope for residential properties and certain exhaust air systems now qualifying under the air-to-water route.
But removing an admin step at application stage does not change what you need to know before quoting. The EPC was quietly filling in baseline property data that fed into heat loss inputs, design assumptions, and system selection. If that information is not coming from an EPC, it needs to come from the survey pack.
What changed
- No EPC required for retrofit applications. Where a valid EPC exists, the certificate number still needs to be provided, but it is no longer expected to block the application.
- Air-to-air heat pumps become eligible. Residential properties only, with the draft guidance signalling a £2,500 grant route.
- Exhaust air systems can qualify under the air-to-water route. Specifically where the system delivers heat through a liquid-based distribution setup.
Those are real changes. They widen the addressable pipeline. They do not reduce the amount of evidence needed to quote accurately or hand a job over cleanly.
What has not changed
MCS standards still apply. Heat loss calculations still need accurate inputs. Emitter sizing, electrics, cylinder requirements, access, controls, and plant position still need capturing. The change is about what blocks the application form, not about what you need to know before a price goes out.
What the survey now carries
Without an EPC acting as a backstop, the survey has to stand up on its own:
- Fabric. Wall construction, loft insulation depth, cavity fill status, and floor type. These go straight into heat loss.
- Glazing. Window types, age, and condition. Affects heat loss and can change the viability of the design.
- Existing heating. Boiler type, fuel, emitters, controls, and distribution context.
- Electrics. Consumer unit condition, spare ways, supply capacity, and any obvious upgrade constraints.
- Emitters and pipework. Radiator types, sizes, locations, and the distribution picture the designer actually needs.
- Hot water. Cylinder presence, condition, likely replacement position, and usable space.
- External conditions. Outdoor unit location, clearances, access, maintenance routes, and neighbour context.
What to capture if air-to-air enters the mix
If air-to-air moves into your product range, the survey still needs to stay operational rather than abstract. The useful capture points are indoor unit locations, room coverage, controls, electrics, and condensate routes. That is what helps the office team quote the job properly and helps the designer hand over without guesswork.
What to check before 28 April
- Survey scope: can the pack stand alone without EPC cross-reference?
- Quoting workflow: can the office quote from the pack alone, or does someone still need to fill gaps by phone?
- Design handoff: when the pack lands with design, is it structured enough to avoid re-questions?
- Customer expectations: are you explaining that the application may be lighter, but the survey still is not?
The commercial point
Wider eligibility is good for pipeline. But margin is still won or lost between the survey and the install. Accurate first-pass quotes, clean handoff, and fewer surprises still come down to one thing: what was captured on site.
See our ASHP survey scope, how we work with installer teams, and what sits inside our deliverables and structured survey packs. If the EPC is no longer filling the gaps, the pack has to do it.
See what a usable pack looks like
If you are reviewing your process ahead of the April changes, compare your current survey scope against a structured pack that is built for quoting, design handoff, and install readiness.