How much does a new boiler cost in 2026?

Boiler costs by type in 2026

UK boiler replacement costs break down into the boiler unit itself, installation labour, and any additional work needed (pipework, controls, flue, power flush, etc).

Boiler type	Unit cost	Install labour	Total (typical)
Combi	£800-£1,800	£800-£1,500	£1,800-£3,500
System	£900-£1,700	£1,000-£2,000	£2,200-£4,000
Regular (heat-only)	£800-£1,500	£1,000-£2,000	£2,000-£3,800

These are averages for a straightforward replacement. Costs go up if you:

• Move the boiler to a different location
• Convert from one type to another (e.g. regular to combi)
• Upgrade pipework or radiators at the same time
• Need a new flue route or condensate drain
• Require scaffolding to access the boiler location

Combi boiler costs

Combi boilers are the most popular choice for UK homes. They heat water on demand and don't need a separate hot water cylinder or cold water tank.

Typical install cost: £1,800 to £3,500 for a like-for-like swap in a 3-bed house.

What affects the price

• Boiler size (output): A 24-28kW combi suits most semis and terraces (£800 to £1,200 for the unit). Larger detached houses need 30-35kW (£1,200 to £1,800).
• Brand: Budget brands like Ideal or Potterton cost less (£800 to £1,000). Premium brands like Vaillant, Worcester Bosch, or Viessmann cost more (£1,200 to £1,800) but often have longer warranties.
• Install complexity: Swapping an old combi for a new one in the same spot is the cheapest job (1 day, £800 to £1,200 labour). Moving it or converting from a regular boiler costs more (2 days, £1,500 to £2,500 labour).

System boiler costs

System boilers heat a hot water cylinder, so you have stored hot water. Good for homes with high hot water demand (multiple bathrooms, large families). They don't need a cold water tank in the loft, so simpler than a regular boiler but more complex than a combi.

Typical install cost: £2,200 to £4,000 including the cylinder.

What affects the price

• Cylinder cost: A new unvented cylinder adds £500 to £1,200 depending on size (150L to 300L). If you're keeping an existing cylinder, the cost is lower.
• Cylinder location: Cylinders go in airing cupboards, utility rooms, or lofts. If you're installing a new cylinder, you need space and access for pipework.
• G3 qualification: Unvented cylinders must be installed by a G3-qualified engineer. Check the installer has this before booking.

Regular boiler costs

Regular boilers (also called heat-only or conventional boilers) work with a hot water cylinder and a cold water tank in the loft. Common in older properties. Less common in new installs because combi and system boilers are simpler.

Typical install cost: £2,000 to £3,800 if you're keeping the existing cylinder and tank. Add £800 to £1,500 if you need a new cylinder or tank.

Additional costs to budget for

On top of the boiler and labour, you might need:

Power flush (£400 to £700)

A power flush clears sludge and debris from the heating system. Most installers recommend it when fitting a new boiler to protect the heat exchanger. Some boiler warranties require it.

Magnetic filter (£80 to £150)

Catches debris circulating in the system. Extends boiler life. Many manufacturers require one for the warranty to be valid.

Smart thermostat (£150 to £300)

Wireless controls like Nest, Hive, or Tado. Not essential, but they let you control heating from your phone and can save 10-15% on bills.

Radiator upgrade (£100 to £250 per radiator)

If you're replacing an old boiler, check whether radiators need replacing or upsizing. Some installers bundle this into the quote.

Flue relocation (£200 to £500)

If the new boiler's flue doesn't align with the old one, you'll need a new route through the wall or roof. Adds labour and materials.

Budget vs premium boilers

All gas boilers sold in the UK must be condensing boilers with a minimum 92% efficiency (ErP A-rated). So even budget models are efficient.

What you pay extra for with premium brands:

• Longer warranties: Budget brands offer 2-5 years. Premium brands offer 7-10 years if installed by an approved installer.
• Quieter operation: Premium boilers have better insulation and quieter pumps.
• Better build quality: Thicker heat exchangers, higher quality components, longer lifespan.
• Easier servicing: Common brands have better parts availability and more engineers familiar with them.

For most homes, a mid-range boiler (Ideal, Baxi, Alpha) offers the best balance of cost and reliability. You'll pay £1,000 to £1,400 for the unit vs £800 for a budget model or £1,600+ for premium.

Grants for boiler replacement

There are no direct grants for gas boiler replacement in 2026. The government wants people to move away from gas, so funding goes to heat pumps instead.

The Boiler Upgrade Scheme offers £7,500 for heat pump installs, but nothing for gas boilers. See our guide on whether heat pumps are worth it to compare costs.

The only support for gas boilers is through ECO4 (Energy Company Obligation), which sometimes replaces broken boilers for low-income or vulnerable households. You need to be on benefits or have a household income under £36,000. Contact your energy supplier to check.

Should you replace or repair?

If your boiler breaks, you have two choices: repair it or replace it. Here's how to decide:

Replace if:

• The boiler is over 12 years old
• Repair cost is over £500
• Parts are hard to source (manufacturer discontinued the model)
• It's broken down multiple times in the past year
• Efficiency is below 85% (older non-condensing boilers)

Repair if:

• The boiler is under 8 years old
• Repair cost is under £300
• It's a simple fix (pressure sensor, pump, diverter valve)
• The boiler is still under warranty

Between 8 and 12 years, it's a judgment call. Get a repair quote and compare it to replacement cost. If the repair is more than a third of a new boiler's cost, replacement usually makes more sense.

Boiler size: how to get it right

An oversized boiler wastes gas by cycling on and off. An undersized one won't heat your house properly. The right size depends on your heat loss, not just the number of bedrooms.

Rough guide for combi boilers:

• 1-2 bed flat or small terrace: 24-28kW
• 3-bed semi or mid-terrace: 28-30kW
• 4-bed semi or detached: 30-35kW
• Large detached or poor insulation: 35-40kW

A good installer will do a heat-loss calculation based on your house size, insulation, and number of radiators. Don't just pick the same size as your old boiler. If you've added loft or wall insulation since the old one was fitted, you might need a smaller boiler now.

How long does installation take?

A straightforward combi-to-combi swap takes 1 day. System or regular boiler installs take 1-2 days depending on cylinder work. Converting from one type to another can take 2-3 days.

You'll be without heating and hot water during installation. Plan around the weather and book early if you need it done in winter.

Choosing an installer

All gas boiler installers must be Gas Safe registered. Check their registration number on the Gas Safe Register website before booking.

What to look for:

• Gas Safe registration. Non-negotiable. Don't use anyone who isn't registered.
• Manufacturer accreditation. Some brands (Worcester, Vaillant, Viessmann) offer extended warranties if installed by an accredited installer. Check if your chosen installer is accredited.
• Insurance-backed guarantee. Look for a 2-5 year workmanship guarantee backed by insurance. If the installer goes out of business, the insurer covers any problems.
• Written quote. Get a detailed quote listing the boiler model, what's included (filter, flush, controls), and what's extra.
• Reviews. Check Trustpilot, Google, or Checkatrade. Look for recent reviews, not just old ones.

Boiler vs heat pump

Heat pumps are the government's preferred replacement for gas boilers. They cost £8,000 to £15,000 to install (after the £7,500 Boiler Upgrade Scheme grant), but running costs are similar to gas or slightly cheaper on the right tariff.

For most people in 2026, a new gas boiler still makes more sense:

• Lower upfront cost (£2,000 to £3,500 vs £8,000+)
• No need to upgrade radiators or insulation first
• Familiar technology, easy to repair, lots of engineers
• Works in any house type without major modifications

Heat pumps make sense if you're building new, you have good insulation, you're replacing an old oil or LPG boiler, or you want to future-proof against gas price rises. See our full comparison in are heat pumps worth it?

The actual cost breakdown

Here's a real-world example for a typical job:

This is typical for a mid-range install with all the recommended extras. You could cut costs by skipping the power flush (not recommended), using a cheaper thermostat, or going for a budget boiler. Or you could add costs by choosing a premium brand or upgrading radiators.

What to check before you commit

Before booking a boiler install:

1. Get three quotes. Prices vary by £500+ between installers. Make sure quotes are for the same spec (boiler size, brand, extras included).
2. Check Gas Safe registration. Verify on the Gas Safe Register website. Ask to see their ID card on the day.
3. Ask about the warranty. How long is it? What does it cover? Is annual servicing required to keep it valid?
4. Clarify what's included. Does the quote include power flush, filter, smart controls, flue, Building Regs notification? Or are those extras?
5. Check lead time. In winter, installers can be booked up for weeks. If your boiler has just broken, ask about emergency slots.

Bottom line

A new gas boiler costs £1,800 to £3,500 for most UK homes. Combi boilers are cheapest and simplest. System and regular boilers cost more because of the cylinder and extra pipework.

Get at least three quotes. Check Gas Safe registration. Make sure the quote includes everything you need (flush, filter, controls). Don't just pick the cheapest quote if it's missing things the others include.

A good boiler, properly installed, will last 12 to 15 years. Spending an extra £300 on a better brand or a proper power flush will save you money over the boiler's lifetime.

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Sources and further reading

1. Gas Safe Register (2025), "Find a Gas Safe registered engineer", gassaferegister.co.uk
2. Department for Energy Security and Net Zero (2025), "Boiler Upgrade Scheme guidance", gov.uk
3. Ofgem (2026), "Default tariff cap level", ofgem.gov.uk
4. Heating and Hotwater Industry Council (2021), "Domestic heating compliance guide", hhic.org.uk
5. Which? (2025), "Best and worst boiler brands", which.co.uk

Related guides

• Combi boiler vs system boiler
• Are heat pumps worth it in the UK?
• Is loft insulation worth it?