Content reviewed 5 Sept 2026

Boiler Replacement Cost UK (2026)

A typical UK boiler replacement costs £2,200–£4,500 fitted in 2026. Heat pumps run £8,000–£14,000 before the £7,500 BUS grant. Here's the breakdown by boiler type, brand, and property size.

Gas boiler replacement (typical 2026 prices)

Combi boiler swap (like-for-like)

£2,200–£3,500

Most common swap. 1-day install. Includes new boiler (24–35kW), flue, magnetic filter, fresh thermostat and system flush.

Combi → system or vice versa

£3,500–£5,500

Bigger job — adds or removes a hot-water cylinder. 2-day install. Common in family homes upgrading from combi for more hot-water capacity.

System or regular (heat-only) swap

£2,500–£4,500

Larger homes with separate hot-water cylinder. Cost rises with system flush complexity and any new controls (smart thermostats add £150–£300).

Heat pump alternative

Air-source heat pump (incl. BUS grant)

£2,500–£6,500

Gross cost £8,000–£14,000 minus the £7,500 Boiler Upgrade Scheme grant (England & Wales). If your home is currently heated by oil, the grant rose to £9,000 in 2026, so net cost is typically £1,000–£5,000. Biomass boilers get £5,000 and air-to-air heat pumps £2,500. Best paired with radiators sized for lower flow temperatures, or underfloor heating. Running costs are typically lower than gas if you have a heat-pump-specific tariff (e.g. Octopus Cosy).

How to get a fair quote

• Get three quotes from Gas Safe registered engineers (or MCS for heat pumps).
• Ask for the make, model and kW rating in writing — not just a total.
• Check the warranty: Worcester Bosch and Viessmann typically offer 10 years with annual servicing.
• Beware "fixed price" boiler websites — useful for ballpark but local installers often beat them by £200–£500.
• If you're on a low income or certain benefits, ask your energy supplier about Energy Company Obligation (ECO) help and check the government's Warm Homes Plan support for a free or subsidised replacement.

Frequently asked questions

How much does it cost to replace a boiler in the UK in 2026?

A typical combi-boiler swap costs £2,200–£3,500 fitted, including the boiler (£900–£1,800), labour (£600–£1,200) and ancillaries (flue, thermostat, system flush). System and regular (heat-only) boilers cost £2,500–£4,500 fitted because the install is more involved.

What's the cost of a heat pump instead?

Air-source heat pumps cost £8,000–£14,000 installed before the Boiler Upgrade Scheme (BUS) grant. The £7,500 BUS grant brings net cost to £2,500–£6,500 — often comparable to a new boiler. Homes currently heated by oil get £9,000, cutting net cost to £1,000–£5,000. Ground-source is £20,000+ and needs land.

What is the Boiler Upgrade Scheme grant?

In England and Wales the BUS pays £7,500 towards an air-source or ground-source heat pump, £9,000 if your home is currently heated by oil, £5,000 towards a biomass boiler and £2,500 towards an air-to-air heat pump. The grant is paid to your MCS-certified installer, so you pay the discounted price. Scotland uses the Home Energy Scotland Grant and Loan (grant plus interest-free loan) instead.

Which boiler brands are most reliable?

Which? and Trustpilot consistently rank Worcester Bosch, Viessmann, Vaillant and Ideal at the top for reliability and warranty support. Avoid no-name imports — the £200 saving up-front rarely outweighs higher service costs and shorter lifespan.

Will I have to replace my boiler with a heat pump?

No. There is no legal deadline forcing households to switch: gas boilers can still be installed and replaced like-for-like through the 2030s. The old plan to ban new fossil-fuel boiler installs from 2035 was dropped, and government policy now uses grants such as the Boiler Upgrade Scheme to encourage heat pumps rather than mandating them.

A new boiler typically saves 15–25% on gas usage versus a 15-year-old unit. Use the Energy Bill Calculator to see what that's worth in real money under the latest Ofgem price cap, or the Property Running Cost Calculator for the full ongoing cost picture.