New boiler cost in 2026: real UK prices explained

Typical installed prices

• Combi swap (like-for-like): £1,800 to £2,800 including a mid-range boiler, filter, flush and controls.
• System boiler with cylinder: £2,500 to £4,000.
• Conversion from heat-only to combi: £2,800 to £4,500 because pipework, gas supply and removal of tanks are involved.

What moves the price

1. Brand and warranty: a Worcester Bosch Greenstar with a 10-year guarantee costs more than a budget model with 5 years, but the guarantee is worth having.
2. Output (kW): a 3-bathroom house needs a bigger combi or a system boiler.
3. Relocation: moving the boiler to a loft or garage adds flue, pipework and a condensate route.
4. Gas pipe upgrade: modern boilers often need 22 mm gas from the meter.
5. Extras that should be included: magnetic filter, chemical flush or powerflush, smart thermostat, Building Regulations notification and warranty registration.

Comparing quotes

Ask every installer for the same three things: the exact model, the warranty length and what is included. A cheap quote that skips the filter and flush often voids the warranty.

We list our from-prices on the pricing page and confirm a fixed figure after a free survey.