How to find a boiler installer you can trust
How to check they are legitimate, the warning signs that should end the conversation, and why the cheapest quote is often the most expensive.
14 July 2026 · 5 min read
Fitting quality matters more than boiler brand. A well-installed budget boiler will outlast a badly installed premium one, and badly fitted gas work can kill people. So this is worth twenty minutes of your time.
The non-negotiable check
Gas Safe registration. It is illegal to work on a gas boiler in the UK without it. Ask for the number, then check it yourself at gassaferegister.co.uk - do not just look at the card, because cards can be faked and registrations lapse.
The register tells you what they are qualified for, too. Being registered for cookers does not qualify someone for boilers.
The warning signs
Cash-only, no paperwork, no VAT. Not a bargain, a liability.
Pressure to decide today. A discount that expires this evening is a sales tactic, not a price.
No written quote. If it is not on paper it does not exist when something goes wrong.
Reluctance to give you the Gas Safe number, or annoyance when you say you will check it.
A quote far below everyone else's. Ask what has been left out, because something has been.
The good signs
They measure your water flow rate before recommending a combi. They count your radiators. They ask about your shower use. They look at the flue route.
They give you a fixed price in writing with the boiler model on it.
They tell you when you do NOT need something. The installer who talks you out of an upsell is usually the one to go with.
Getting more than one quote
Two installers looking at the same job can be £800 apart, and the difference is often in what is included rather than who is greedier. Without a second quote you have no way of knowing which one you are looking at.
That is the entire reason this site exists: one form, up to three Gas Safe registered installers who cover your postcode, and no obligation to use any of them.