The easiest way to make a BUS job messy is to treat the evidence file as something you can tidy up later. In practice, most BUS problems start earlier than that. They start when a quote is issued against half-checked site evidence, when the EPC position is misunderstood, or when the installer cannot quickly show what information sat behind the application.
This page is the practical checklist version. It is not trying to restate the whole scheme. It is trying to answer a narrower question: what should a competent installer team have in the record before they quote, apply, and redeem.
Start with the date, not the headline
| Situation | What applies | Practical effect |
|---|---|---|
| Applications active on 5 April 2026 | Current live guidance is Version 4.2. | For retrofit properties, a valid EPC still needs to be provided at voucher application stage unless the property is an eligible self-build. |
| Applications properly made on or after 28 April 2026 | Ofgem says draft Version 5 is expected to apply from that date. | Retrofit properties are expected to be able to apply without a valid EPC, but installers then need to provide fallback evidence where no valid EPC exists. |
Checklist lane one: what current live applications still need
- A valid EPC reference at voucher application stage for retrofit properties under the current live Version 4.2 rule set.
- A quote that matches what was actually issued to the property owner. Ofgem says the submitted values may be checked against the quote reference number.
- Quote details that can be evidenced later: total quote amount before the grant is deducted, total cost of the heat pump unit, installer quote reference, and quote date.
- A record the office can defend if someone later asks what sat behind the application, the quote, or the chosen system route.
Checklist lane two: what draft Version 5 says to provide when there is no valid EPC
Ofgem’s draft Version 5 does not say “no EPC, no evidence needed.” It replaces one evidence route with another. The draft wording says that where a property does not have a valid EPC, installers must provide evidence on behalf of the property owner to demonstrate eligibility. The draft says the following should be provided where available:
- a recent utility bill dated within the last 3 months or a recent fuel receipt
- photographs of the existing heating system
- certificate number of an expired EPC, if one is available
That is the key operating shift. The absence of a valid EPC does not remove the need for a documented building baseline. It means the installer needs to be more deliberate about where that baseline now comes from.
What should already be in the file before you submit a voucher application
| Record item | Why it matters |
|---|---|
| Current or expired EPC position | The team needs to know whether the application sits in the live v4.2 lane or the planned late-April no-valid-EPC lane, and what fallback evidence is therefore needed. |
| Quote copy and quote reference | Ofgem says submitted values should match the quote issued to the customer and may be checked against the quote reference number. |
| Existing heating evidence | Photos and notes on the current heating system stop the application basis from becoming vague later. |
| Property baseline evidence | Utility bill, fuel receipt, older EPC details, and relevant customer documents help explain the property where a current EPC is missing or stale. |
| Survey pack that can stand on its own | Room data, electrics, access, cylinder, emitter and outdoor-unit context still need to support the quote and design route whether or not the EPC rule changes. |
What installers forget after submission
- Retention: current BUS guidance says the installer must retain a copy of any information relied on when making voucher and redemption applications for six years.
- Accuracy duty: if the installer becomes aware that information provided by the property owner is false or inaccurate, the guidance says they must notify Ofgem within 14 days and should not redeem the voucher.
- Application support file: it is not enough that the surveyor saw the evidence on the day. The office needs the same evidence kept with the job record.
A practical BUS-era folder structure
The cleanest approach is to stop treating BUS evidence as a separate admin pile. Keep it with the same job record the quote and design team already need.
- Folder 1: quote, quote reference, customer details, application-stage notes
- Folder 2: EPC position, expired EPC details if relevant, utility bill or fuel receipt if relevant
- Folder 3: existing heating-system photos and notes
- Folder 4: heat-loss, room, electrical, emitter, cylinder and outdoor-unit survey evidence
- Folder 5: anything later relied on for voucher redemption or audit response
Bottom line
The right BUS checklist is not complicated. It is just disciplined. Know which rule set applies on the application date. Keep the evidence that supports that rule set with the same job record as the quote and survey pack. Make sure the submitted quote details match the real quote. Then keep the relied-on information for the period Ofgem expects.
Sources
Next useful pages
If the question is policy dates, start with the main BUS changes guide. If the question is what evidence should actually be in the file, use this checklist together with the EPC evidence guide and the MCS documentation guide.