How much does a new boiler cost in 2026?

A new boiler including installation typically costs £2,000–£4,500 in the UK. A combi boiler (the most popular type) costs £1,800–£3,500 installed, a system boiler costs £2,000–£4,000, and a conventional (regular/heat-only) boiler costs £2,000–£4,000. The exact cost depends on the brand, model, output rating (kW), complexity of installation, and where you live. Replacing a like-for-like boiler is cheaper than switching boiler type (e.g. conventional to combi) because of additional pipework changes.

What type of boiler do I need?

It depends on your home and hot water demand. A combi boiler is best for small to medium homes (1–2 bathrooms) — it heats water on demand, no tank needed. A system boiler suits larger homes (2–3+ bathrooms) with a hot water cylinder but no cold water tank. A conventional boiler is for homes with both a hot water cylinder and a cold water tank in the loft — common in older properties. If you have multiple bathrooms or high hot water demand, a system or conventional boiler delivers better water pressure to multiple taps simultaneously.

Is it worth getting a new boiler?

If your current boiler is 10–15+ years old, inefficient (rated D–G on an ErP label), or breaking down frequently, replacing it can save £200–£580 per year on gas bills. Modern A-rated condensing boilers are at least 92% efficient compared to 60–80% for older models. The payback period on a new boiler is typically 5–10 years through energy savings. A new boiler also comes with a warranty (typically 5–12 years), improved reliability, and can increase your property's EPC rating.

Can I get a grant for a new boiler?

The Boiler Upgrade Scheme offers £7,500 towards an air source heat pump or £5,000 towards a ground source heat pump — but this only applies to heat pumps, not gas boilers. For gas boilers, the ECO4 scheme may provide free or subsidised replacement boilers if you're on a qualifying benefit and your current boiler is broken or inefficient. Some local councils also offer boiler grants. Energy suppliers administer ECO4 — contact yours to check eligibility.

New Boiler Costs UK 2026 — Combi, System & Conventional Prices | PocketWise

A new boiler is a significant investment, but the right choice can cut your energy bills for years. Here’s what you’ll pay in 2026.

Average Costs at a Glance

Boiler type	Boiler cost (supply only)	Installation cost	Total installed
Combi boiler	£800–£2,000	£800–£1,500	£1,800–£3,500
System boiler	£900–£2,200	£1,000–£2,000	£2,000–£4,000
Conventional (regular)	£800–£2,000	£1,000–£2,000	£2,000–£4,000
Combi-to-combi swap	Lowest complexity	£800–£1,200	£1,800–£2,800
Conventional-to-combi conversion	Additional work needed	£1,500–£2,500	£2,500–£4,500

Boiler Types Explained

Type	How it works	Best for	Pros	Cons
Combi	Heats water on demand — no tank or cylinder	1–2 bathroom homes	Compact, no tank/cylinder, instant hot water	Can struggle with 2+ taps running simultaneously
System	Uses a hot water cylinder but no cold water tank	2–3+ bathroom homes	Good water pressure to multiple taps, compatible with solar thermal	Needs space for a cylinder
Conventional (regular)	Uses both a hot water cylinder AND a cold water tank	Older homes, large properties	High water flow to multiple taps, suits older heating systems	Needs most space, least efficient setup

Cost by Brand

Brand	Budget	Mid-range	Premium	Warranty
Worcester Bosch	—	£1,200–£1,800	£1,800–£2,500	Up to 12 years
Vaillant	—	£1,100–£1,700	£1,700–£2,300	Up to 10 years
Baxi	£700–£1,000	£1,000–£1,400	—	Up to 10 years
Ideal	£600–£900	£900–£1,400	£1,400–£1,800	Up to 12 years
Viessmann	—	£1,200–£1,600	£1,600–£2,200	Up to 12 years
Alpha	£500–£800	£800–£1,100	—	Up to 7 years
Glow-worm	£600–£900	£900–£1,200	—	Up to 7 years

prices are supply-only

What Size Boiler Do I Need?

Combi Boilers

Home size	Bedrooms	Bathrooms	Recommended output
Small flat/house	1–2	1	24–28 kW
Medium house	3	1–2	28–34 kW
Large house	4+	2+	35–42 kW

System/Conventional Boilers

Home size	Radiators	Hot water cylinder	Recommended output
Small–medium	Up to 10	120–150 litres	12–18 kW
Medium–large	10–15	150–210 litres	18–25 kW
Large	15+	210–300 litres	25–35 kW

Installation Costs — What Affects the Price

Factor	Impact on cost
Like-for-like swap	Cheapest — minimal additional work
Changing boiler type (e.g. conventional to combi)	+£500–£1,500 — removing tanks, changing pipework
Moving the boiler location	+£500–£1,000 — new pipework, flue routing
New flue	+£100–£300
Magnetic filter (MagnaClean)	+£100–£200 (recommended)
Power flush	+£300–£600 (cleans the system, recommended for older systems)
New thermostat/controls	+£100–£400
Smart thermostat (Hive, Nest)	+£150–£300 installed
Scaffolding (if flue is high up)	+£200–£500

Annual Running Costs

Boiler efficiency	Annual gas cost (3-bed semi)	Saving vs old boiler
Old boiler (60% efficient)	~£1,600	—
Old boiler (70% efficient)	~£1,370	—
Old boiler (80% efficient)	~£1,200	—
New A-rated (92%+ efficient)	~£1,040	£160–£560 per year

Based on typical gas consumption and unit rates

Energy Savings Over Time

Current boiler rating	Annual saving with new A-rated boiler	10-year saving
G-rated (below 70%)	£400–£580	£4,000–£5,800
F-rated (70–74%)	£300–£430	£3,000–£4,300
E-rated (74–78%)	£230–£340	£2,300–£3,400
D-rated (78–82%)	£160–£240	£1,600–£2,400

Grants and Funding

Scheme	What’s available	Who qualifies
ECO4	Free or heavily subsidised boiler replacement	Low-income homes, households on qualifying benefits (UC, Pension Credit, etc.)
Boiler Upgrade Scheme	£7,500 (air source heat pump) / £5,000 (ground source) — but not for gas boilers	Homeowners in England/Wales replacing fossil fuel heating
Home Energy Scotland	Interest-free loans and cashback for energy efficiency	Scotland residents
Nest (Wales)	Free boiler replacement for eligible households	Wales, low income
Local council schemes	Vary by area	Check with your council

How to Get ECO4 Funding

Step	Action
1	Check you’re on a qualifying benefit (Universal Credit, Pension Credit, Child Tax Credit, Income Support, etc.)
2	Contact your energy supplier — they administer ECO4
3	A surveyor visits to assess your home and existing boiler
4	If eligible, the boiler is replaced at no cost (or reduced cost)

Choosing an Installer

What to check	Why it matters
Gas Safe registered	Legal requirement — illegal for unregistered engineers to work on gas appliances
Manufacturer accredited	Worcester Bosch, Vaillant etc. accredited installers often offer longer warranties
Get 3 quotes	Prices vary significantly between installers
Check reviews	Checkatrade, Trustpilot, Google reviews
Written quote	Itemised breakdown of boiler, parts, and labour
Warranty terms	Longer warranty = better (12 years is the current market best)
Aftercare	Annual servicing included?

Warning Signs You Need a New Boiler

Sign	What it means
Boiler is 15+ years old	Likely running at 60–80% efficiency
Frequent breakdowns	Repair costs adding up — may exceed replacement cost
Strange noises (banging, kettling)	Internal components failing
Yellow flame (should be blue)	Incomplete combustion — potentially dangerous
Radiators take a long time to heat	Reduced efficiency or circulation problems
Rising energy bills	Boiler losing efficiency
Parts no longer available	Manufacturer has discontinued the model
Carbon monoxide alarm activating	Immediately stop using the boiler and call a Gas Safe engineer

New Boiler Costs UK 2026 — Combi, System & Conventional Prices

Contents