How Much Does It Cost to Replace a Combi Boiler?
£1,800 – £3,800
supply and fit
Replacing a combi boiler costs between £1,800 and £3,800 for supply and installation, with the range reflecting differences in brand, output rating, and installation complexity. A like-for-like replacement in the same location is at the lower end; moving the boiler, upgrading the flue, or fitting a larger output unit adds to the cost.
Average cost
£1,800 – £3,800
supply and fit
Prices vary by region, property type and tradesperson. Always get at least two quotes.
What affects the price?
Boiler brand - budget models (Ideal, Baxi, Ferroli) cost £800-£1,200 for the unit; premium models (Worcester Bosch, Vaillant, Viessmann) cost £1,200-£2,000+
Output rating - a larger kW output boiler for a bigger home or multiple bathrooms costs more than a standard 24-28kW unit
Location change - moving the boiler to a different position requires new pipework and possibly a new flue, adding £300-£800
Additional works - magnetic filter, smart thermostat, and system flush add £150-£400 in total
Labour vs materials
Labour for a combi replacement typically runs £400-£700. The boiler and ancillary materials account for the bulk of the remaining cost.
Questions to ask your tradesperson
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