When homeowners decide to apply for Boiler Upgrade Scheme funding, they often focus first on the grant amount. But the difference between two heat-pump quotations can involve much more than price: the equipment, design, building work, warranty and aftercare may all differ.
The official Boiler Upgrade Scheme (BUS) is available for qualifying properties in England and Wales. An MCS-certified installer makes the Ofgem voucher application on the owner's behalf. Before accepting a quote, ask the following ten questions.
1. Is my property genuinely eligible?
Ask the installer to explain why your property and existing heating system meet BUS rules. Ownership, location, existing fuel and previous public funding can affect eligibility. Most new-build developments and social housing are excluded, while certain qualifying self-build properties may be supported.
Do not rely on an advertising headline that says every homeowner is approved.
2. Which heat-pump type are you proposing?
An air-to-water heat pump connects to a wet central-heating system. A ground source heat pump uses energy from the ground and usually involves additional site work. Air-to-air systems have different installation characteristics and a separate grant category for residential properties.
Ask why the recommended system suits the rooms, hot water needs and space available at your property.
3. How has the heat demand been calculated?
A careful heat-loss assessment helps establish the required heating capacity. Ask for a clear explanation of assumptions about insulation, room temperatures, radiator sizes and any planned home improvements.
An oversized or undersized system may operate less effectively than one designed around the building.
4. What is included in the fixed quotation?
Request an itemised description of equipment and work. Does the price include radiators, a hot-water cylinder, electrics, pipework, controls, disposal of existing equipment and reinstatement after installation?
If some costs are provisional, ask what could cause them to change and how variations will be approved.
5. How much will the grant deduct?
Under current rules, qualifying air-to-water or ground source heat pumps generally receive £7,500. Eligible residential air-to-air systems receive £2,500. Certain off-gas-grid homes replacing oil or LPG heating with an eligible air-to-water or ground source system can receive £9,000 until 31 March 2027.
The quote and final invoice should show the full grant discount clearly. You should not be asked to pay the grant portion and claim it back yourself.
6. Who files the application and confirms consent?
Your MCS-certified installer applies through Ofgem. Ofgem contacts you to confirm the installer is acting with your consent and to verify relevant information. Ask who will track application progress and how they will update you if Ofgem requests more evidence.
A valid EPC is not mandatory for applications made on or after 28 April 2026, although the installer still needs the relevant eligibility evidence.
7. What is the installation schedule?
Get dates for any survey, enabling works, delivery, heating disruption, commissioning and handover. Ofgem's voucher period is generally three months after issue, or six months for a ground source heat pump. Ask the installer to explain how the schedule fits the voucher and what happens if a delay arises.
Do not confuse these deadlines with a guaranteed time to complete every project.
8. What running-cost assumptions are you using?
Ask to see the estimated seasonal efficiency, assumed electricity tariff and annual heating demand. The installer should explain that actual bills depend on weather, occupancy and energy prices.
A quote promising identical savings for every home is a reason to ask further questions.
9. What warranty and aftercare do I receive?
Request written terms for equipment warranties, installation workmanship, servicing and breakdown support. Find out who handles problems during the first winter and what maintenance may be necessary to keep warranties valid.
A lower-cost installation is not necessarily better value if essential aftercare is missing.
10. How do I compare competing quotes fairly?
Place quotations side by side and review identical categories: heating capacity, hot-water provision, radiator work, electrics, control systems, grant value, total price, warranty and completion dates.
If specifications differ, ask each installer to explain the design rationale. Choosing only the cheapest figure can hide important exclusions.
What should you do next?
Gather two or more suitable quotes and retain the written evidence. For accessible background information on how to apply for Boiler Upgrade Scheme support, visit Berks Insulation's guide, then discuss installation-specific questions with an MCS-certified installer.
Quick FAQs
Can I send my own grant application to Ofgem?
No. The ordinary process is managed by a certified installer on your behalf.
Is a heat pump automatically free after the grant?
No. The grant reduces eligible upfront costs; any remaining amount depends on the quote.
Can a government grant be used for a replacement gas boiler?
Not under BUS, which supports specified low-carbon heating systems.
Conclusion
The right questions make it easier to compare grant offers and identify a credible installation plan. Confirm eligibility, demand a transparent quote and understand the equipment and aftercare before signing.
Official References: GOV.UK, How to apply and What you can get; Ofgem, BUS Property Owners (checked 4 November 2026).
