The most valuable comparison is between complete designs, not outdoor unit brands. Verify the installer, ask for a room-by-room heat loss assessment and insist on a clear handover.
Start with the right credentials
For a Boiler Upgrade Scheme installation, the installer must be MCS certified for the relevant technology. Check the business on the MCS directory and ask which consumer code covers the contract. GOV.UK points homeowners to RECC and HIES consumer protection schemes. A logo on a quotation is not the same as checking the active listing.
Ask who will survey, design, install and commission the system. If subcontractors are involved, find out which certified business takes responsibility for the completed installation and your support after handover.
Demand a design you can understand
A credible proposal starts with room-by-room heat loss and explains how the proposed radiators or underfloor heating will keep each room comfortable. It should identify the outdoor location, expected sound assessment, hot-water cylinder and controls. Ask for the expected seasonal performance and annual electricity use, with assumptions.
A higher-output unit is not automatically safer. Oversizing can create cycling and unnecessary cost; undersizing can leave a home cold or reliant on backup heat. Invite the installer to explain the design choices in plain English.
Make quotes genuinely comparable
Energy Saving Trust advises getting at least three quotes. Request the same breakdown from each: equipment and model, radiator and pipework changes, cylinder, electrics, old system removal, commissioning, grant deduction, payment stages and exclusions. Ask what could change the price after the survey.
The 2026 government evaluation found 91% of surveyed Boiler Upgrade Scheme recipients were satisfied with their heating system 9 to 21 months after installation. Satisfaction was high, yet only 26% felt completely confident that they could programme it to minimise running costs. That gap is a strong reason to take the handover seriously.
Set the handover standard before you sign
Ask for a demonstration of the heating schedule, hot-water settings and what to do if the unit shows an error. Get the final design, commissioning records, warranty terms, service schedule and MCS certificate. GOV.UK says the MCS certificate should be issued within ten days of installation.
Confirm who answers a winter call if a room is not warming as expected. A responsive local installer with clear aftercare can be more valuable than a small difference in equipment price.
A note about the numbers
Prices, grants and tariffs can change. The dated figures above come from the linked sources and are examples unless explicitly described as a published average. Your installer should assess your property before giving a final design or quotation.