A new boiler is one of the bigger one-off bills a homeowner faces, and the quotes you get back can vary by thousands for what looks like the same job. The price comes down to the type of boiler, the make, and how much pipework has to change - so it pays to understand what you are actually paying for before you sign anything.
A straight combi swap is usually £1,800-£3,000 supplied and fitted. Moving to a different system, or a premium make with a long warranty, pushes it to £3,000-£4,500+.
Typical UK Prices
| Job | Typical price |
|---|---|
| Combi swap (like-for-like) | £1,800-£3,000 |
| Conventional → combi conversion | £3,000-£4,500 |
| New system boiler + cylinder | £2,500-£4,000 |
| Premium make, 10-year warranty | £3,000-£4,500+ |
| Extra: power flush | £300-£600 |
| Extra: moving the boiler position | £300-£800 |
What Drives the Price
- Boiler type
- A like-for-like combi swap is cheapest. Changing system type means new pipework, tanks removed or fitted, and more labour.
- Make and warranty
- Budget brands cost less up front; premium makes cost more but come with 7-10 year warranties that can be worth it long term.
- Pipework and position
- Moving the boiler, upgrading the gas supply, or adding a filter and new controls all add to the quote.
- Your home
- A flat with easy access is quicker than a three-storey house with the boiler in the loft.
Combi, System or Conventional?
- Combi
- Heats water on demand, no tanks. Ideal for smaller homes and the most popular choice. Hot water can dip if several taps run at once.
- System
- Works with a hot water cylinder - better for homes with two or more bathrooms and higher hot-water demand.
- Conventional
- Cylinder plus a loft tank. Usually only kept where the existing setup or water pressure suits it.
Repair or Replace?
- Under 8 years old with a one-off fault - repair almost always wins, see our boiler repair cost guide
- Over 12 years old and breaking down most winters - replacement usually pays back in efficiency
- If a single repair tops half the price of a new boiler, get a replacement quote too
- An old, inefficient boiler quietly costs you on every gas bill
How to Cut the Cost
- Get three quotes - prices for the same job vary widely between installers
- A like-for-like swap is far cheaper than relocating or changing system type
- Don't over-spec the output - a correctly sized boiler is cheaper to buy and run
- Ask what warranty is included; a longer one can offset a higher price
Before the Installer Visits
Combi or cylinder? Where is the boiler now? A photo of the existing unit helps the quote.
Cold radiators or sludge may mean a power flush is needed - see radiator not heating up.
An itemised quote - boiler, labour, controls, flush, warranty - lets you compare like for like.
Will a New Boiler Actually Save You Money?
A modern A-rated boiler runs at over 90% efficiency, where an old one limping along at 70% is throwing nearly a third of your gas money up the flue. On an average home that can mean a few hundred pounds a year - so a replacement isn't only about avoiding breakdowns, it's about what the old unit quietly costs you every winter. It rarely pays to scrap a healthy boiler early just for efficiency, but once yours is unreliable, the running-cost saving makes the sums add up faster than people expect.
How Long Will the Job Take?
A straight combi swap is often a one-day job. Converting from a conventional system, moving the boiler, or upgrading the gas supply can stretch it to two or three days, with the heating off in between - worth knowing if you're booking it in winter. A good installer tells you up front how long you'll be without heat and hot water, and whether making-good like boxing in pipes or patching plaster is included or extra.
All boiler work must be done by a Gas Safe registered engineer. Prices are typical 2026 UK ranges and vary by make and region. If your current boiler has packed in and you need heat now, run the boiler not working checklist first, or get an emergency heating engineer on the way.