Quick answer
A new boiler in 2026 typically costs from around £1,800 to £3,500 supplied and fitted for a like-for-like swap, with the exact figure depending on boiler type, brand and job complexity.
A combi like-for-like swap runs about £1,800 to £3,200. System and heat-only boilers sit a little higher, and relocating or converting the system can add £800 to £1,500 or more.
Installing a boiler is gas work that must be carried out by a Gas Safe registered engineer, so always get two or three written quotes for your own home.
Replacing a boiler is one of the larger one-off bills a UK household faces, and quotes can vary widely for what looks like the same job. The headline figure you see advertised is usually for a straightforward like-for-like swap.
The real number depends on the boiler type, the brand, where the boiler sits, and how much extra work your system needs at the same time.
The figures below are indicative ranges for 2026 and include both the boiler and a standard installation by a Gas Safe registered engineer. Always get two or three written quotes for your own home, as prices vary by region, property and installer.
Indicative new boiler costs by type and complexity
The three common domestic boiler types in the UK are the combi (heats water on demand, no cylinder), the system boiler (works with a hot-water cylinder) and the heat-only or regular boiler (works with a cylinder and one or two tanks in the loft). Within each type, the price climbs as the job gets more involved.
| Boiler type | Like-for-like swap (same spot) | Relocation or conversion |
|---|---|---|
| Combi (supply + fit) | ~£1,800 – £3,200 | ~£2,800 – £4,500 |
| System (supply + fit) | ~£2,200 – £3,600 | ~£3,200 – £5,000 |
| Heat-only / regular (supply + fit) | ~£2,000 – £3,400 | ~£3,000 – £4,800+ |
Indicative supply-and-fit ranges, last checked 2026. A "conversion" means changing system type, for example moving from a heat-only boiler and cylinder to a combi, which adds pipework and removal labour.
Indicative new boiler costs by property type
Property size is one of the biggest drivers of the final bill, because a larger home needs a higher-output boiler and usually more pipework, more radiators and a longer install.
The ranges below are typical supplied-and-fitted figures for a like-for-like gas boiler in 2026 and assume a reasonably straightforward job; awkward flue runs, a powerflush or a system conversion push the figure towards (or above) the top of each band.
| Property type | Typical boiler type | Installed cost (indicative) |
|---|---|---|
| Flat / apartment (1–2 bed) | Combi | ~£1,600 – £3,000 |
| Mid-terrace (2–3 bed) | Combi | ~£2,000 – £3,500 |
| Semi-detached (3 bed) | Combi or system | ~£2,500 – £4,000 |
| Detached (4+ bed) | System or heat-only | ~£3,000 – £5,500+ |
Indicative supply-and-fit ranges, last checked 2026. Larger detached homes with two bathrooms often need a system boiler and cylinder, which sits at the upper end. Source: aggregated UK installer price guides — get written quotes for your own home.
Indicative new boiler costs by brand
Brand is the other big lever on price. The figures below are supply-only (the boiler unit before installation), to show how the brands compare on the hardware alone — installation, flue, controls and any extras are on top.
As a rough rule, premium German brands sit highest, the established UK volume brands sit in the middle, and the budget ranges sit lowest. A longer manufacturer warranty (often 10–12 years on premium models, when fitted by an accredited installer) can be worth paying for.
| Brand | Positioning | Combi unit supply-only (indicative) |
|---|---|---|
| Worcester Bosch | UK market leader, premium | ~£900 – £2,500 |
| Vaillant | Premium German engineering | ~£800 – £2,000 |
| Viessmann | Premium, high-efficiency | ~£1,000 – £2,500 |
| Ideal | Mid-range value | ~£600 – £1,300 |
| Baxi | Long-established, mid/budget | ~£700 – £1,500 |
| Alpha | Budget | ~£600 – £1,200 |
Indicative supply-only unit prices, last checked 2026; installation, flue, controls and extras are additional. Ranges reflect entry-level to higher-output combi models and will vary by retailer and model. Always compare the fitted price and warranty length, not just the unit price.
What actually affects the price
Two homes can get very different quotes for the same boiler type. Beyond the brand and the output (a larger family home needs a higher-output boiler than a small flat's unit), most of the variation comes from a handful of common "extras" that may or may not be in a headline quote.
This is why two quotes for the "same job" can be hundreds of pounds apart — one includes the flush, filter and controls, the other doesn't. Use the table below to check exactly what each quote covers.
| Extra / additional work | Indicative cost | When it applies |
|---|---|---|
| Vertical flue (through the roof) | ~£350 – £550 | When the boiler can't vent horizontally through an outside wall; may also need scaffolding. |
| Plume management kit | ~£80 – £150 | When the flue terminates near a window, door or boundary and the steam plume must be redirected. |
| Gas supply pipe upgrade | ~£200 – £800 | When the existing pipe is too narrow for a modern boiler's gas demand and must be upsized back to the meter; cost depends on the run length and floor access. |
| Magnetic system filter | ~£80 – £120 | Fitted on the return pipe to catch sludge; often a warranty condition and well worth having. |
| Power / chemical flush | ~£300 – £600 | To clear sludge from an older system before the new boiler goes on; frequently a warranty condition. |
| Smart thermostat | ~£150 – £250 | When you upgrade the controls at the same time (e.g. a learning or app-controlled thermostat). |
| Carbon monoxide alarm | ~£15 – £40 | A cheap, sensible add-on (and a legal requirement in some rented and new-build settings); your engineer can advise on siting. |
| Replacement radiators | ~£100 – £300 each (fitted) | If old radiators are corroded or undersized for the new system; priced per radiator. |
Indicative extra costs, last checked 2026. These are additional to the boiler-and-fit figures above and vary by property and installer.
A few further points worth knowing:
- Brand, model and warranty. Premium brands cost more up front but a longer manufacturer warranty (10–12 years on some models) can offset that if it reduces future repair risk.
- Flue position. A simple horizontal flue through an outside wall is cheapest; a vertical roof flue or a long run adds parts and labour (see the table above).
- Condensate routing. If the condensate pipe needs re-routing to meet current standards, that is extra labour.
- Access and removal. Awkward loft tanks, scaffolding for a roof flue, or removing an old cylinder all add cost.
Cost of moving or converting a boiler
If you want the new boiler somewhere different — or you're changing system type — that is no longer a like-for-like swap, and the price reflects the extra pipework, flue, electrics and labour. The further the boiler moves, the more it costs.
These figures are on top of the boiler itself unless stated, and a relocation is typically a one-to-three-day job rather than a single day.
| Move / conversion | Indicative cost | Why |
|---|---|---|
| Reposition within the same room | ~£300 – £600 | Short pipe and flue extension, minimal making good. |
| Move to a different room (same floor) | ~£400 – £700 | Longer pipe runs, a new flue position and more making good. |
| Move to a different floor | ~£800 – £2,800 | Vertical pipe runs, possible flue and electrical rerouting, more disruption. |
| Move into the loft | ~£1,200 – £1,400+ | New flue, condensate and a loft platform; scaffolding (if needed) can add ~£650 – £1,200. |
| Heat-only/system → combi conversion | ~£3,000 – £4,500 | Removing tanks and cylinder, re-pipework and upgrading to mains pressure (boiler included). |
| Back boiler → combi conversion | ~£3,500 – £4,500 | Removing the fireplace back boiler and siting a new combi elsewhere; usually the most involved job (boiler included). |
Indicative ranges, last checked 2026; relocation figures are additional to the boiler unless the row notes the boiler is included. A Gas Safe engineer must assess siting, clearances and flue routing for your property.
Grants and help with the cost
There is no universal grant for a new gas boiler in the UK, but there are targeted schemes — and one big point of confusion worth clearing up first.
ECO4 is the main route to a free or subsidised gas boiler replacement
The Energy Company Obligation (ECO4) is the main government-backed route that can help with a like-for-like gas boiler replacement. It obliges larger energy suppliers to fund energy-efficiency measures — including repairing or replacing a broken or inefficient boiler — in lower-income and fuel-poor households. To be eligible you typically need to:
- be on a qualifying means-tested benefit (for example Universal Credit, Pension Credit, Income-Based JSA/ESA, Income Support, Child or Working Tax Credit, or Housing Benefit); and
- own (or privately rent, with the landlord's permission) a home with an EPC rating of D to G — the least efficient homes (F and G) are the highest priority.
Households not on benefits may still qualify through their local council under ECO4 Flex. The scheme is currently due to run to the end of 2026.
Two important caveats: a full free replacement is not guaranteed — funding is finite, a contribution is sometimes required, and the measure offered depends on what makes your home most efficient — and boiler replacement is generally not available for private-rented properties as part of an ECO4 package.
Check eligibility and current rules on the official GOV.UK Energy Company Obligation page or via Ofgem.
The Boiler Upgrade Scheme is for heat pumps, not gas boilers
A common point of confusion: the government's Boiler Upgrade Scheme in England and Wales is for low-carbon heating such as air source and ground source heat pumps (and biomass in some cases). It does not apply to a replacement gas combi, system or heat-only boiler.
If you are simply swapping one gas boiler for another, you will not qualify for that grant. Heat-pump grants are a separate decision with their own running-cost and installation considerations.
Other help with energy costs
- Warm Home Discount. A one-off £150 rebate off your electricity bill for eligible low-income households (broadly, those on Pension Credit Guarantee Credit or certain means-tested benefits in England and Wales). It does not pay for a boiler, but it helps with running costs over winter. See GOV.UK Warm Home Discount.
- Scotland — Warmer Homes Scotland and the Home Energy Scotland Grant & Loan. Warmer Homes Scotland offers eligible, lower-income households free energy-efficiency measures that can include a new boiler; the Home Energy Scotland Grant & Loan offers grants/interest-free loans for heating upgrades. See Home Energy Scotland.
- Northern Ireland — Affordable Warmth and NISEP. The Affordable Warmth Scheme supports lower-income households (income threshold applies) with heating and insulation improvements, and the Northern Ireland Sustainable Energy Programme (NISEP) funds further energy-efficiency measures. Check with your local council or the NI Housing Executive.
Grant rules, amounts and deadlines change — figures indicative, last checked 2026. Always confirm current eligibility on the official GOV.UK, Ofgem or devolved-nation pages before relying on a scheme.
Repair or replace?
A new boiler is a big outlay, so it is worth weighing it against a repair. As a rough guide, if your boiler is well over ten years old, has had repeated breakdowns, or a single repair quote is approaching half the cost of a new unit, replacement often makes more financial sense.
Our guide on repairing or replacing your boiler walks through the trade-offs in detail.
How much will a new boiler save me?
A modern A-rated condensing boiler is more than 90% efficient, whereas an old G-rated boiler can be around 65% efficient — so a chunk of every gas bill on an old unit is wasted heat.
The Energy Saving Trust publishes indicative annual savings for replacing an old gas boiler with a new A-rated model and a full set of heating controls.
The savings are largest in bigger, less-insulated homes and smallest in flats (which are naturally insulated by neighbouring properties), and they shrink the closer your old boiler's rating already is to an A.
| Old boiler rating | Detached house | Semi-detached | Flat |
|---|---|---|---|
| G (≈70% or less) | ~£500 / year | ~£320 / year | ~£130 / year |
| F | lower than G | lower than G | lower than G |
| E | smaller again | ~£200 / year* | modest |
| D | smallest | smallest | smallest |
Indicative annual savings from replacing an old gas boiler with an A-rated condensing boiler plus controls. Source: Energy Saving Trust estimates, last checked 2026. The headline £500/£320/£130 figures are for replacing a G-rated boiler; savings fall as the old rating improves (F, then E, then D), because there is less waste to recover. *Example given by the Energy Saving Trust: an E-rated boiler replaced with a combi in a semi-detached house saves roughly £200/year. Real-world savings vary with how you heat your home and how well it is insulated.
Where does boiler cover fit in?
Boiler cover (and breakdown insurance) generally pays for repairs and call-outs on an existing, working boiler, not for a planned replacement of an old or end-of-life unit. Most policies exclude boilers above a certain age and won't fund a full upgrade.
What cover can do is reduce the sting of repair bills while your current boiler still has life in it, and some policies include an annual service that helps it last longer. If you're weighing up the value, see is boiler cover worth it? and read what boiler cover actually includes before you buy.
How to keep replacement costs down
- Get at least two or three written quotes and check exactly what each includes (flush, filter, controls, removal, making good).
- Stick with a like-for-like swap unless you have a strong reason to relocate or convert.
- Ask whether the quoted price includes a system flush and a magnetic filter — both protect your investment.
- Compare the manufacturer warranty length, as a longer warranty can offset a higher headline price.
- Avoid replacing in the depths of winter if you can plan ahead, as demand and prices peak then.
How much is a new combi boiler in 2026?
A like-for-like combi swap is typically around £1,800 – £3,200 supplied and fitted, with premium brands and any extra pipework, flue or flush work pushing it higher. Relocating or converting the system can add £800 – £1,500 or more.
How long does a boiler replacement take?
A straightforward like-for-like swap is usually done in a day. A conversion (for example heat-only to combi), a relocation, or a job needing a powerflush or roof flue can take two days or more.
Can I get a grant for a new gas boiler?
Possibly, through the Energy Company Obligation (ECO4), which is the main route to help with a like-for-like gas boiler replacement for lower-income or fuel-poor households (on a qualifying benefit, or via ECO4 Flex, with an EPC of D–G).
A full free replacement is not guaranteed and funding is finite. The Boiler Upgrade Scheme does not apply to gas boilers — it is for heat pumps and other low-carbon heating. Scotland and Northern Ireland run their own schemes.
Always check the official GOV.UK, Ofgem or devolved-nation guidance for your circumstances.
Does boiler cover pay for a new boiler?
Generally no. Cover is designed for repairs and breakdowns on a working boiler, not planned replacement of an old unit, and most policies exclude boilers over a certain age. It can, however, soften repair costs while your current boiler is still serviceable.
How often should a boiler be replaced?
Many gas boilers last around 10–15 years with regular servicing. Frequent breakdowns, parts becoming hard to source, or rising repair costs are signs it may be more economical to replace than keep repairing.
Protect your boiler between now and replacement
If your boiler still has life left, cover can keep repair bills predictable. Compare policies from our selected panel of providers in minutes.
Compare boiler coverAll prices are indicative ranges for the UK in 2026 and will vary by property, region and installer. This article is information, not financial or installation advice. We compare cover from a selected panel of providers, not the whole market, and may earn a commission. Always obtain written quotes and use a Gas Safe registered engineer for any boiler work.