Quick Answer
A new boiler in the UK costs £1,500–£4,500 fully installed, depending on boiler type, brand, and your home size. Most households pay around £2,000–£2,500 for a mid-range combi boiler fitted by a Gas Safe engineer.
Your boiler is one of the most important — and expensive — appliances in your home. When it breaks down or reaches the end of its life, the cost of a replacement can feel daunting. This guide gives you the real numbers: average prices by boiler type, house size, and brand, plus everything you need to know before getting quotes.
All prices below are for supply and installation by a qualified Gas Safe registered engineer, and are based on 2026 UK market rates.
In this guide
New Boiler Cost by Type
The type of boiler you need depends on your home size, hot water demand, and existing heating system. Here are the three main types and their installed costs:
| Boiler Type | Installed Cost | Best For | Hot Water Storage? |
|---|---|---|---|
| Combi boiler | £1,500 – £3,500 | Flats, 1–3 bed homes | No (instant) |
| System boiler | £1,800 – £3,800 | 3–4 bed homes, high demand | Yes (cylinder) |
| Conventional (regular) | £2,000 – £4,500 | Older homes, large families | Yes (tank + cylinder) |
| Heat pump (hybrid) | £4,000 – £8,000 | Well-insulated homes | Yes (cylinder) |
Combi boilers are by far the most popular choice in the UK. They heat water on demand — no tank, no cylinder — making them ideal for smaller homes. If you're replacing a combi with another combi, installation is straightforward and costs are at the lower end.
If you're considering moving away from gas entirely, read our guide on heat pump vs gas boiler for an honest cost comparison.
New Boiler Cost by House Size
Larger homes need a more powerful boiler with a higher output (measured in kW). Output requirements drive up the unit price. Here's what to budget based on your property:
| Property Size | Boiler Output | Budget (combi) | Mid-Range (combi) |
|---|---|---|---|
| 1 bed flat / studio | 24–25 kW | £1,500 – £2,000 | £2,000 – £2,500 |
| 2 bed home | 25–28 kW | £1,700 – £2,200 | £2,200 – £2,800 |
| 3 bed home | 28–30 kW | £1,800 – £2,400 | £2,400 – £3,000 |
| 4 bed home | 30–35 kW | £2,200 – £2,800 | £2,800 – £3,500 |
| 5+ bed home | 35–42 kW | £2,500 – £3,500 | £3,200 – £4,500 |
New Boiler Cost by Brand
Brand choice significantly affects price. Budget brands can save you money upfront but may cost more in repairs long-term. Here's how the major UK brands compare:
| Brand | Tier | Installed Cost (combi) | Warranty |
|---|---|---|---|
| Viessmann | Premium | £2,800 – £4,000 | Up to 10 years |
| Worcester Bosch | Premium | £2,500 – £3,800 | Up to 12 years |
| Vaillant | Premium | £2,400 – £3,600 | Up to 10 years |
| Ideal | Mid-range | £1,900 – £2,800 | Up to 7 years |
| Baxi | Mid-range | £1,800 – £2,700 | Up to 7 years |
| Alpha | Budget | £1,500 – £2,200 | 2–5 years |
| Glow-worm | Budget | £1,500 – £2,300 | 2–5 years |
💡 Tip
Worcester Bosch and Viessmann consistently top Which? reliability surveys. If you plan to stay in your home long-term, the higher upfront cost is usually worth it. A cheap boiler that needs a £400 repair every two years quickly becomes more expensive than a premium model.
What Affects the Cost of a New Boiler?
Beyond brand and size, several factors push the final price up or down:
Like-for-like vs conversion
Replacing a combi with another combi in the same location is the cheapest option. Moving the boiler or converting from a conventional system to a combi adds £300–£1,000+ due to extra pipework and labour.
Flue type and position
A standard horizontal flue through an external wall is included in most quotes. A vertical flue through the roof, a longer flue run, or a concentric flue for a shared space adds cost.
Magnetic filter and scale reducer
Most Gas Safe engineers will recommend fitting a magnetic filter (e.g. Magnaclean) to protect the new boiler from sludge. This adds £100–£200 but is worth it — many manufacturers require one for the warranty.
Smart thermostat
A basic programmer is usually included. Upgrading to a smart thermostat (Hive, Nest, Tado) adds £100–£250 fitted.
Radiator flushing / power flush
If your existing system has sludge buildup, your installer may recommend a power flush before fitting the new boiler. This costs £300–£600 and protects your investment. Read more in our guide on what is a power flush.
Region and labour rates
London and the South East carry a 15–25% premium over the Midlands and North. The same boiler installed in Manchester will typically cost less than in London.
To avoid surprises, always ask your engineer for an itemised quote. Use GetQuickHelp to get quotes from multiple Gas Safe engineers in your area and compare them side by side.
What's Included in the Installation Price?
A standard boiler installation quote should include:
- ✓Removal and disposal of old boiler
- ✓Supply of new boiler unit
- ✓Standard flue (horizontal, up to 1 metre)
- ✓New gas pipe connection (if needed)
- ✓Pipework connections to existing system
- ✓Commissioning and testing
- ✓Gas Safe certificate
- ✓Manufacturer warranty registration
It should not include (without being separately quoted): power flush, new radiators, additional pipework runs, smart thermostats, or scale reducers. If a quote seems unusually low, check what it excludes.
How to Save Money on a New Boiler
| Method | Potential Saving | Notes |
|---|---|---|
| Get 3+ quotes | £200 – £800 | Prices vary significantly between installers |
| Avoid winter peak | £100 – £300 | Boiler demand drops in spring/summer |
| Boiler Upgrade Scheme grant | Up to £7,500 | Heat pumps only — see gov.uk/boiler-upgrade-scheme |
| ECO4 scheme | Full replacement free | If on certain benefits — check eligibility |
| Finance / pay monthly | £0 upfront | Some installers offer 0% for 12–24 months |
| Mid-range over premium brand | £400 – £1,000 | Ideal or Baxi vs Worcester Bosch |
If you're on a low income or receive certain benefits, you may qualify for a free boiler replacement through the ECO4 scheme. Check eligibility at gov.uk before spending anything. Also see our guide on the Boiler Upgrade Scheme if you're considering a heat pump.
Should You Replace or Repair Your Boiler?
A good rule of thumb: if the repair cost exceeds half the price of a new boiler, and your boiler is over 10 years old, replacement is usually the better financial decision.
Here are the key signs your boiler needs replacing rather than repairing:
- →The boiler is 12–15+ years old
- →Repair bills are becoming frequent (more than once a year)
- →Parts are becoming hard to source
- →The boiler runs on an old G-rated efficiency (pre-2010)
- →Energy bills have risen significantly with no explanation
- →The boiler makes banging, kettling, or gurgling noises
Modern A-rated boilers are 90%+ efficient. If your current boiler is G-rated (60–70% efficient), a replacement will typically save you £200–£400 per year on heating bills — meaning it pays for itself over time. Use our guide to choosing the right boiler to help you decide.
Frequently Asked Questions
How long does a boiler installation take?+
A straightforward combi-for-combi replacement typically takes one day (5–8 hours). Conversions, larger systems, or boiler relocations can take 2–3 days.
Can I install a boiler myself?+
No. Gas boiler installation is legally required to be carried out by a Gas Safe registered engineer in the UK. An unregistered installer cannot issue a Gas Safe certificate, which you will need for your property records and when selling.
How long does a new boiler last?+
A well-maintained boiler should last 10–15 years. Premium brands like Worcester Bosch and Viessmann often exceed this. Annual servicing is the single biggest factor in longevity.
Does a new boiler reduce my energy bills?+
Yes — if you're replacing an old G-rated boiler with a modern A-rated one. Savings of £200–£400/year are typical for a 3-bed home switching from an old conventional boiler to a modern combi.
Do I need a Gas Safe certificate after installation?+
Yes. Your installer must provide a Gas Safe certificate (also called a Building Regulations compliance certificate) when the work is complete. Keep this safe — you'll need it when selling your home.
What is the cheapest way to get a new boiler?+
Get at least 3 quotes, consider a mid-range brand (Ideal, Baxi), and check if you qualify for ECO4 (free replacement) or the Boiler Upgrade Scheme. Avoid peak winter demand when engineer rates are highest.
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