New boiler cost UK
As of October 2026, Checkatrade’s new boiler cost guide reports:
| Item | Typical figure | Notes |
|---|---|---|
| Boiler supply only | £1,200–£10,000 | Wide range by type and brand |
| Installation labour | £1,000–£2,000 | Day rates often ~£300 |
| Total with extras | £3,000–£15,000 | Most household jobs |
| Combi / system / conventional unit (avg) | ~£1,500 | Guide average in their table |
| Like-for-like combi swap | £2,500–£4,000 | Supply + install band |
| Biomass (manual-fed) unit | ~£10,000 | Supply only in same table |
Those ranges include typical filters and controls only when the installer prices them in — always read the quote line by line. Magnetic filters are often £60–£160 supply plus £50–£150 to fit; Wi‑Fi controllers around £150 in the same guide.
Combi boiler cost
Combi boiler cost is the figure most UK homeowners search for because combis heat water on demand without a cylinder. For a straight swap in the same cupboard with a similar flue, budget the £2,500–£4,000 band above. Converting from a regular (heat-only) system to a combi usually takes longer — Checkatrade notes about 1.5–2 days versus 4–6 hours for a simple swap — so labour rises.
Size the combi by hot-water flow rate as well as central-heating kW. A bigger kW badge does not fix undersized radiators. Use the Boiler Size Calculator and, if rooms feel cold, check emitters with the radiator BTU calculator.
Boiler replacement cost factors
- Like-for-like vs system change. Same position, same fuel, same type is cheapest.
- Flue route. Vertical flues, longer runs and plume kits add parts and labour.
- Moving the boiler. Checkatrade’s moving-boiler guide (October 2026) lists moving an existing boiler around £600–£1,000 (average £800), plus flue extensions, pipework and controls — a mid-range combi move-and-replace example averages about £2,650 in their table.
- Fuel type. LPG and oil have different appliance and compliance paths; oil needs OFTEC.
- Region and access. Flats, parking and scaffolding for flues affect day rates.
- Water quality extras. Power flush, inhibitor and filters protect the warranty.
System and regular boilers
System boilers still need a hot-water cylinder but not a cold-water tank in the loft. Regular (conventional) boilers use both. Checkatrade’s average unit price for system and conventional boilers in the 2026 table is also around £1,500 supply, with the same £1,000–£2,000 installation band — but cylinder replacement, zone valves and re-piping can push the project above a combi swap.
Keep a system or regular layout when you have high simultaneous hot-water demand (multiple bathrooms) that a combi cannot meet comfortably. Ask your Gas Safe engineer to confirm; do not size from rule-of-thumb charts alone for unusual properties.
Worked example: three-bed combi swap
Worked example
Three-bedroom semi, existing combi on an external wall, flue can be reused with a like-for-like concentric terminal. Guide average unit £1,500 + labour mid-point £1,500 = £3,000, sitting inside the £2,500–£4,000 like-for-like band. Add a magnetic filter (~£150 fitted) and a Wi‑Fi thermostat (~£150) → about £3,300 before any radiator upgrades.
Answer: Expect roughly £3,000–£3,500 for a straightforward combi replacement with filter and controls; get Gas Safe quotes on the same specification.
Safety and grants
Gas work must be carried out by a Gas Safe registered engineer. Wrong flue installation and incomplete combustion are life-safety risks — never treat boiler fitting as DIY. If you are replacing a fossil-fuel system with a heat pump instead, check current Boiler Upgrade Scheme amounts on GOV.UK (£7,500 for eligible air-to-water heat pumps in England and Wales, with a time-limited £9,000 rate for some off-gas oil/LPG replacements). Hybrid heat-pump-plus-boiler systems are not eligible for BUS.
When you know the kW you need, open the Boiler Size Calculator. For low-carbon alternatives, see the air source heat pump cost guide.
How much is a new boiler by scenario
Use scenarios rather than a single “average UK boiler price”:
- Emergency like-for-like combi. Aim for the £2,500–£4,000 supply-and-install band with a stock appliance your engineer can warrant.
- Planned upgrade with controls. Add filter, smart thermostat and possibly a power flush — often £3,000–£4,500 total on a simple property.
- System or regular with cylinder work. Budget past £4,000 once cylinders, pumps or zone valves join the job.
- Oil or LPG. Appliance prices and technician availability differ; get OFTEC (oil) quotes separately from gas work.
- Electric boiler. Checkatrade’s related notes put electric supply-and-install examples around £3,000–£4,200 depending on specification — running costs and fuse-board capacity matter more than the sticker price.
Manufacturer cashback and trade packages change week to week. Ask the engineer to show the boiler model, output (kW), flow rate (l/min for combis), warranty length, and whether the quote includes flushing, chemicals, filter, thermostat, flue terminal and disposal of the old unit.
Ways to save without cutting safety
- Keep the boiler position if the flue and condensate route still comply — moves are a major cost driver.
- Fix leaks and sludge first so the new heat exchanger is not damaged in month one.
- Match radiator capacity before chasing a huge boiler — cold rooms are often emitter or balancing problems.
- Compare three Gas Safe quotes on the same model shortlist rather than three random “package deals”.
- Service annually to protect warranty and efficiency; a cheap install with no aftercare is a false economy.
If your long-term plan is a heat pump, talk to an MCS installer before you spend on a premium gas appliance you may replace in a few years. If you need heat this month, a solid mid-range combi fitted correctly beats waiting for a grant timeline you have not modelled. Either way, confirm the final design and installation with a qualified Gas Safe engineer — online kW charts are not a substitute for a site survey.
Warranty and what quotes omit
Boiler warranties often require an annual service and a system filter. An install quote that skips inhibitor, cleansing and a filter can look £200 cheaper and still cost you the warranty after a sludge failure. Ask how many years of parts and labour are covered, whether the warranty is with the manufacturer or a third party, and who registers it.
Extras commonly omitted from headline “boiler deals” include:
- Condensate upgrades — especially in freezing locations where pipework needs insulation or a soakaway rethink.
- System cleansing — chemical clean or power flush on older radiators.
- Thermostat wiring — smart controls that need a neutral or hub placement.
- Scaffold or tower hire — for awkward flues above hardstanding.
- Landlord or Building Control notifications where relevant for rented stock.
For households on oil, get the tank condition checked while you replace the boiler; a new appliance on a failing tank is a false saving. For LPG, confirm meter or bottle arrangements and ventilation. Electric-only homes should involve an electrician early — load calculations matter as much as the boiler brochure.
Write the successful quote into a simple scope PDF with model number and exclusions listed. That document is what you hold the engineer to on installation day, not a remembered phone estimate. Keep the benchmark certificate and any Building Regulations notification with the appliance manual — you will need them for future servicing, insurance claims and when you sell.
If two Gas Safe quotes differ by more than about 20% on the same model, ask each engineer to explain flue length, cleansing and controls rather than defaulting to the cheapest number. Under-specified installs are how “new boiler cost” becomes “call-out cost” three months later.
Frequently Asked Questions
How much is a new boiler in the UK?
As of Checkatrade’s October 2026 guide, supply-only boilers typically cost £1,200–£10,000. With installation and extras, most households pay £3,000–£15,000. A like-for-like combi replacement is often £2,500–£4,000.
How much does a combi boiler cost to supply and install?
Checkatrade lists an average combi unit around £1,500, with installation commonly £1,000–£2,000. Simple like-for-like jobs often total £2,500–£4,000.
What affects boiler replacement cost?
Boiler type and output, fuel, whether the job is like-for-like, flue changes, filters and controls, radiator or pipework upgrades, and moving the boiler to a new location.
Do I need a Gas Safe engineer?
Yes. Gas boilers in the UK must be installed by a Gas Safe registered engineer. Oil boilers should be fitted by an OFTEC-registered technician. DIY gas work is illegal and unsafe.
Is a heat pump grant available instead of a new gas boiler?
The Boiler Upgrade Scheme can provide £7,500 toward an eligible air-to-water heat pump in England and Wales (with a higher £9,000 rate for some off-gas oil/LPG replacements for a limited period). Hybrid heat pumps are not eligible for BUS.
Sources
- Checkatrade — New boiler cost UK 2026 — Supply £1,200–£10,000; installed £3,000–£15,000; combi like-for-like £2,500–£4,000; labour £1,000–£2,000.
- Checkatrade — Moving a boiler cost — Relocation extras such as flue, pipework and controls.
- GOV.UK — Boiler Upgrade Scheme grant amounts — £7,500 air/ground source; £9,000 uplift rules for oil/LPG off-gas.
- Gas Safe Register — Find a registered gas engineer.
When you are ready to estimate materials or cost for your project, open the Boiler Size Calculator and enter your measurements.