If you're pricing up a new boiler, you'll find quotes ranging from around £1,800 to well over £4,500, and it's not always obvious why. As Gas Safe registered heating engineers covering Diss and the surrounding Suffolk and Norfolk villages, we fit boilers week in, week out. Here's an honest breakdown of what drives the price, so you can compare quotes with confidence.
The biggest factor is what you're starting with. A straightforward like-for-like combi swap, where the new boiler goes in the same spot as the old one, is the cheapest job. Replacing an ageing heat-only boiler with hot water cylinder and tanks in the loft with a combi is a bigger piece of work, because the pipework needs rerouting and the old kit stripping out.
These figures include the boiler, flue, magnetic filter, chemical flush and labour. They're a guide, not a quote, because every house is different, but they reflect what we see locally in Suffolk and Norfolk rather than London prices.
A good installation is more than hanging a box on the wall. When quotes differ by several hundred pounds, it's usually because one includes work the other quietly leaves out. Before you compare prices, check each quote covers the same scope.
Be wary of a quote that skips the system flush or filter. Sludge in old radiators is the number one killer of new boilers, and most manufacturers require a proper clean and filter for the warranty to stand.
Older properties around Diss, Eye and Harleston often throw up extras that a tick-box online quote won't catch. Undersized gas supply pipe is a common one: older 15mm runs frequently can't feed a modern combi, so upgrading to 22mm adds pipework time. Moving a boiler from an airing cupboard to the kitchen, long flue runs through thick walls, or a condensate pipe with no nearby drain all add labour.
On the other hand, some things keep costs sensible. If your existing boiler position, flue route and pipework are all sound, a straight swap can often be done in a day. Choosing a mid-range boiler rather than a premium brand can save £300 to £500 without a big difference in reliability, provided it's sized correctly and serviced annually. Oversizing is a genuine waste of money; most three-bed homes need a far smaller output than people assume, and a heat loss calculation is the right way to size it.
Always get a proper survey rather than a price over the phone. An engineer who visits can check your gas supply, water pressure, flue options and radiators, which means no surprise extras on the day. Ask what warranty comes with the boiler and whether the installer will register it for you, and confirm they're Gas Safe registered; you can check any engineer's number free on the Gas Safe Register website.
Cheapest isn't always best value. A quote £200 lower that omits the flush and filter can cost you far more when the heat exchanger clogs in year three. Equally, you shouldn't pay inflated prices: two or three local quotes will quickly show you the fair market rate for your specific job.
A like-for-like combi swap is usually done in one day. A conversion from a conventional boiler to a combi, including removing the cylinder and loft tanks, typically takes two to three days.
If your boiler is under ten years old and the repair is modest, fixing it usually makes sense. Once repairs approach £400 to £500 on a boiler over 12 to 15 years old, replacement is generally the better investment, especially as newer condensing boilers cut gas use noticeably.
Yes. Your installer must notify the work through Gas Safe, and you'll receive a Building Regulations compliance certificate in the post. Keep it safe along with the warranty registration, as solicitors ask for it when you sell the house.