UK Boiler Cost Calculator
Plan a new boiler with confidence. Estimate the supply price, installation cost, annual running cost, 15-year ownership cost and simple payback against your current boiler — all in one place.
Independent UK energy planning from PowerGuardian. Illustrative figures — not a supplier quote.
See all your savings in one place
Enter your home details once and get personalised savings, supplier picks, recommended actions, calculators and guides on My PowerGuardian.
Figures reviewed June 2026 and updated monthly where appropriate. All results are estimates.
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Bathrooms drive combi sizing (hot water). Home type and insulation drive heat demand.
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How the Boiler Cost Calculator Works
The calculator estimates the total cost of a new UK boiler in four stages. First it works out your home's annual heat demand from home type, bedrooms, bathrooms and insulation. It then applies your current boiler's age-based efficiency and your new boiler's rated efficiency to convert that heat demand into fuel used and fuel cost. Finally it adds the supply price, standard installation and any extras to give a lifetime figure and a simple payback against staying on your existing boiler.
How Much Does a New Boiler Cost in the UK?
Fully installed, most UK homeowners pay between £2,000 and £4,500 for a new boiler including labour. A basic combi swap in an easy-access location can come in around £2,000, while a premium combi with a powerflush, smart thermostat and a boiler relocation can reach £4,500 or more. System and regular boilers are typically £200–£400 more to install than a like-for-like combi swap.
Combi, System or Regular?
Combis heat water on demand and are cheapest to fit — ideal for smaller homes with one bathroom. System boilers pair with a hot water cylinder and cope better with two or more bathrooms running at once. Regular (heat-only) boilers suit older homes with existing feed-and-expansion tanks in the loft and are also common when planning a future move to a heat pump.
How Much Could a New Boiler Save You?
Replacing a 15-year-old boiler running at around 75% efficiency with a modern A-rated model at 93% can cut your annual gas use by roughly 20%. On a typical £900/year gas bill that's £150–£200 saved every year — often the biggest single running-cost win in the home.
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