How much does a new boiler cost UK?

A new boiler in the UK typically costs £1,800 to £4,500 including installation. A combi boiler costs £1,800–£3,500 installed, a system boiler costs £2,000–£4,000, and a regular (conventional) boiler costs £2,000–£4,500. The cost depends on the brand, output size, complexity of installation, and your location. A straightforward like-for-like combi swap is cheapest.

How long does a new boiler last?

A modern condensing gas boiler typically lasts 12 to 15 years. Premium brands like Worcester Bosch and Vaillant can last 15 to 20 years with regular servicing. Most manufacturers offer warranties of 5 to 12 years. Annual servicing (£80–£150) helps maintain efficiency and extends lifespan.

Is it worth replacing a 15-year-old boiler?

Usually yes. A 15-year-old boiler is likely running at 70–80% efficiency compared to 90–94% for a modern condensing boiler. This means you could save £100–£300 per year on gas bills. If your boiler needs frequent repairs or has become unreliable, replacement is almost certainly worthwhile. The payback on the efficiency savings alone is typically 6–12 years.

Can I get a free boiler on benefits UK?

You may be able to get a free or heavily subsidised boiler replacement through the ECO4 scheme if you receive certain means-tested benefits (such as Universal Credit, Pension Credit, or Child Tax Credit) and have an inefficient boiler. Contact your energy supplier or the government's Simple Energy Advice service to check eligibility.

How Much Does a New Boiler Cost in the UK?

Replacing your boiler is one of the biggest home expenses, but also one of the best ways to cut gas bills. Here is what it costs, which type to choose, and how to pay for it.

New Boiler Costs by Type

Boiler type	Boiler cost (supply)	Installation cost	Total installed cost
Combi boiler	£800–£2,000	£800–£1,800	£1,800–£3,500
System boiler	£900–£2,200	£1,000–£2,000	£2,000–£4,000
Regular (conventional) boiler	£900–£2,200	£1,100–£2,300	£2,000–£4,500

What Adds to the Cost

Factor	Additional cost
Moving the boiler to a new location	£500–£1,500
Converting from regular to combi	£500–£1,000 (removing tanks and cylinder)
New flue route (through roof instead of wall)	£200–£600
Magnetic filter (recommended)	£100–£200
Powerflush (cleaning radiators)	£300–£600
New thermostat and controls	£150–£500
Scaffolding (if flue is high up)	£200–£500
Gas pipe upgrade	£200–£500

Boiler Types Compared

Feature	Combi	System	Regular
Hot water cylinder	No — heats on demand	Yes — in airing cupboard	Yes — in airing cupboard
Cold water tank in loft	No	No	Yes
Best for	1–3 bed, 1 bathroom	3–4 bed, 2+ bathrooms	Large houses, existing system
Hot water to multiple taps	Reduced flow rate	Good — cylinder stores hot water	Good — cylinder stores hot water
Space needed	Minimal	Needs cylinder space	Needs cylinder and loft tank space
Installation complexity	Simplest	Medium	Most complex
Most popular in UK	Yes (~70% of new installs)	~20% of new installs	~10% of new installs

Costs by Brand

Brand	Combi cost (supply only)	Warranty	Reputation
Worcester Bosch	£1,000–£2,000	Up to 12 years	Premium — consistently top-rated
Vaillant	£1,000–£1,900	Up to 10 years	Premium — excellent reliability
Ideal	£750–£1,400	Up to 12 years	Good value mid-range
Baxi	£700–£1,300	Up to 10 years	Reliable mid-range
Alpha	£600–£1,000	Up to 7 years	Budget-friendly
Viessmann	£1,000–£1,800	Up to 10 years	German engineering, growing UK market

Costs by Home Size

Home size	Recommended output	Typical boiler	Installed cost
1–2 bed flat	24–28 kW combi	Ideal Logic+ 24	£1,800–£2,500
3 bed semi	28–32 kW combi	Worcester 8000 30	£2,200–£3,200
4 bed detached (1 bathroom)	32–35 kW combi	Vaillant ecoTEC Plus 35	£2,500–£3,500
4+ bed (2+ bathrooms)	18–25 kW system boiler	Worcester Greenstar 8000	£2,800–£4,000

Running Cost Comparison

Boiler age/type	Efficiency	Annual gas bill (3-bed home)	Annual saving vs old boiler
Old non-condensing (15+ years)	70–80%	£1,050–£1,200	—
Modern condensing combi	90–94%	£800–£900	£150–£300
New condensing system boiler	90–93%	£820–£920	£130–£280

Based on typical gas consumption of 12,000 kWh/year at current gas prices.

How to Choose the Right Size

kW output	Radiators	Bedrooms	Bathrooms
24–28 kW	Up to 10	1–2	1
28–32 kW	10–15	3	1–2
32–35 kW	15–20	4	1 (combi limit)
System boiler 18–25 kW	15–20+	4+	2+

If you have more than one bathroom with simultaneous demand, a system boiler with a cylinder is usually better than a combi.

Warranty Comparison

Brand	Max warranty	Conditions
Worcester Bosch	12 years	Must be installed by Worcester accredited installer
Ideal	12 years	Must be installed by Ideal Max accredited installer
Vaillant	10 years	Must be installed by Vaillant Advance installer
Baxi	10 years	Must be registered with Baxi Works
Alpha	7 years	Standard installation
Viessmann	10 years	Must be installed by Viessmann trained installer

Tip: Always use a Gas Safe registered engineer. Using a brand-accredited installer usually gets you a longer warranty at no extra cost.

Free or Subsidised Boiler Schemes

Scheme	What it covers	Eligibility
ECO4	Free or subsidised boiler replacement	Means-tested benefits (UC, Pension Credit, etc.) + inefficient existing boiler
Boiler Upgrade Scheme (BUS)	£7,500 grant towards heat pump	All homeowners — but replaces boiler with heat pump, not another gas boiler
Local authority schemes	Varies by council	Check with your local council
Energy supplier obligations	Some offer boiler grants	Contact your supplier directly

Gas Boiler vs Heat Pump

Factor	Gas boiler	Air source heat pump
Installed cost	£1,800–£4,500	£10,000–£18,000 (£7,500 BUS grant available)
Running cost (3-bed home)	£800–£1,000/year	£700–£1,000/year
Lifespan	12–15 years	20–25 years
Maintenance	Annual service £80–£150	Annual service £100–£200
Carbon emissions	Moderate (fossil fuel)	Low (electric)
Disruption to install	1 day (like-for-like swap)	2–5 days, may need new radiators
Future-proofing	Gas boilers may be phased out for new builds	Government-backed long-term solution

For most replacement situations today, a gas boiler is still the pragmatic and affordable choice. If you can afford the upfront cost (with the BUS grant), a heat pump is the longer-term investment.

How to Finance a New Boiler

Method	Typical rate	Monthly payment (£2,500 boiler, 5 years)
Boiler finance (0% from installer)	0%	£42
Personal loan	5–8%	£47–£50
Credit card (0% purchase)	0% for 12–24 months	Min payment, pay off in 0% period
Savings	N/A	—

Many boiler installers offer 0% finance over 2–5 years, which can be the cheapest way to spread the cost.

How to Get Quotes

Step	Details
Get at least 3 quotes	Prices vary by £500–£1,500 for the same job
Check Gas Safe registration	Verify at GasSafeRegister.co.uk
Ask about brand accreditation	Gets you a longer warranty
Check what is included	Powerflush, thermostat, magnetic filter, removing old boiler
Ask about aftercare	Some include first-year service

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