Boilers
How do I choose a boiler installer — and what should a good quote include?
3 min read · Reviewed for accuracy before publishing
Start with the non-negotiable: the engineer must be Gas Safe registered, and you're entitled to see the card. Beyond that, the difference between a good installer and a cheap headline is what's written down. A proper quote is fixed, in writing, and spells out the boiler and flue, a full system flush (not a rinse), a filter, controls set up and explained, making good, removal of the old boiler, the warranty length and what keeps it valid, and any finance terms in full. If a quote is vague on those — or the price seems too good — that's usually because something on that list is missing.
The floor: Gas Safe and insurance
Gas Safe registration is a legal requirement for anyone working on your gas boiler — ask to see the card and check the number if you want to. Alongside it, a proper installer carries public liability insurance and stands behind the work. This is the baseline, not the selling point.
What a real quote spells out
The specific boiler and flue, a genuine system flush and a filter, controls configured and explained, the old boiler taken away, making good afterwards, the manufacturer warranty length and the conditions that keep it valid (registration at install, then an annual service), and any 0% finance terms in full. Everything on paper, fixed, before you commit — so 'while we're here' extras can't appear.
The tell of a cheap headline
A very low number usually means a small budget boiler, no flush, no filter, skipped commissioning paperwork (which can void your warranty claim), or a day-rate that balloons on the day. Compare what's included, not just the figure at the top — the cheapest quote and the best-value quote are rarely the same one.
David founded Datum after years on the tools across heating and plumbing. He writes the boiler and cost guides from what actually happens on real installs.