DATA-BACKED GUIDE · UPDATED JULY 2026
New boiler cost in the UK: combi vs system prices
Swapping out a tired boiler is one of those jobs most of us only do once a decade, so it is hard to know what a fair figure looks like. The right price depends on the type of boiler, the make, and how much pipework needs changing. A like-for-like combi swap is a different job to a full system conversion, and quotes will not look the same for each. The real prices below come from actual bills, so you can see what people paid rather than a sales quote.
The quick version
- A combi boiler tends to cost less to fit than a system boiler because it needs no separate cylinder or tank.
- The boiler unit itself is only part of the bill; labour, flue, controls and any pipework changes add up too.
- Moving the boiler to a new spot, or converting from one type to another, pushes the price up because of the extra pipework and making good.
- A quality new boiler with a long warranty often works out cheaper over its life than the cheapest option, since call-out and parts costs later can eat into any saving made upfront.
- Where you live and who you book affects the quote as much as the boiler itself; a national firm usually charges more than a good local installer for the same job.
- Two quotes for what looks like the same job can differ mainly because one includes a chemical flush or extra radiators and the other does not, so ask exactly what is covered before comparing figures.
What people actually paid
Real prices, in people's own words
- £2,000“a 30kw one at a cost of £2k January 2021”
- £2,000“£2k”
- £2,400“I recently had a Worcester boiler installed (no other work, just a new boiler) and that was £2400 on it's own (including VAT and labour).”
- £2,500“just paid 2500 for a new combi (similar cost boiler)”
- £2,500“just paid 2500 for a new combi”
- £3,500“We paid £3500 to have a new boiler fitted and the old back boiler removed for my mum”
Genuine amounts posted publicly. We publish the price and the quote, never the person.
Why the price varies so much
No two boiler jobs are identical, which is why quotes bounce around so much. A straight like-for-like combi boiler swap in the same location is the quickest and cheapest scenario, since the pipework, flue run and electrics are already in place and the engineer is largely just disconnecting the old unit and fitting the new one. Once you add a hot water cylinder for a system boiler, extra radiators, a new flue run, or a chemical flush of a sludgy system, the labour and parts climb, because each of those is effectively a separate job bolted onto the swap. Brand matters as well; premium makes with a decade-long warranty sit above budget units, reflecting both the build quality and the longer cover behind them. Who does the work matters just as much as what is being done. A sole trader working from a van has lower overheads than a large national installer with a call centre and fleet of branded vehicles, and that difference in running costs shows up in the price even when the boiler on the wall is identical. Where you live plays a part too, and a national firm usually quotes above a good local installer for the very same work, partly because of regional demand and partly because of how each business is set up to operate.
How to pay less
- Get three written quotes from Gas Safe registered local installers and compare like for like, checking each one covers the same work before you set them side by side.
- Ask whether a like-for-like combi boiler swap is possible before agreeing to any relocation or conversion, since staying in the same spot avoids the extra pipework and labour that pushes a job into a higher price band.
- Check what the warranty covers and how long it lasts, since a longer warranty can save you later on parts and call-outs even if the upfront price is a bit higher.
- Book outside the autumn rush, as engineers are often keener on price in spring and summer when boilers are not breaking down in the cold.
- Ask for the quote broken down into boiler unit, labour, flue and any pipework or flush, so you can see exactly where the money goes and challenge any part that looks steep.
- Get a local installer to quote alongside any national firm; the two can differ for identical work, and a smaller local firm often has lower overheads to pass on.
Common questions
Is a combi or system boiler cheaper to install?
A combi boiler is usually cheaper to fit because it heats water on demand and needs no separate cylinder or loft tank. A system boiler suits homes with high hot water demand and several bathrooms, but the extra cylinder and pipework add to the cost. Check the real prices below to compare both.
How long does a new boiler take to fit?
A straightforward like-for-like swap is often done in a day. A conversion from one boiler type to another, or moving the unit to a different room, can take two to three days because of the extra pipework and making good afterwards.
Do I need a Gas Safe engineer?
Yes. Any gas boiler work must be carried out by a Gas Safe registered engineer by law. Always ask to see the card and check the registration before work starts, and keep the paperwork for your warranty and any future sale.
Why do boiler quotes vary so much for what sounds like the same job?
The boiler itself is only one line on the bill. Labour, flue work, controls, any pipework changes and whether a chemical flush is included can all differ between quotes even when the boiler model is the same. Ask each installer for a breakdown rather than just a total, so you are comparing the same scope of work.
Does moving the boiler add much to the cost?
Yes, relocating a boiler usually costs more than a like-for-like swap because of the extra pipework, a new flue run, and the work needed to make good the old and new locations. If keeping the boiler where it is works for your home, a straight swap will almost always be the cheaper route.
Is it worth paying more for a boiler with a longer warranty?
Often, yes. A longer warranty can cover parts and labour for issues that would otherwise mean a call-out charge further down the line, so the cheapest unit on the day is not always the cheapest boiler over its lifetime. Weigh the warranty length against the upfront price rather than looking at the sticker price alone.