Boiler replacement costs 2026
Gas boiler replacement remains the most common HVAC job in Wales. For most homes, a modern condensing combi boiler is the most practical upgrade. Costs depend on boiler brand, output size, and installation complexity.
Combi boiler replacement (supply and fit):
- Budget brands (Baxi, Ideal): £1,600–2,400
- Mid-range (Worcester Bosch 2000i, Vaillant ecoFIT): £2,000–3,200
- Premium (Worcester Bosch Greenstar, Vaillant ecoTEC exclusive): £2,500–4,000
System boiler with unvented cylinder:
- Mid-range: £2,800–4,500
Regular (heat-only) boiler:
- Mid-range: £2,200–3,800
Additional costs commonly required:
- Magnetic filter (Adey MagnaClean or equivalent): £80–150
- Power flush before new installation: £350–600
- Extended flue or through-wall flue: £200–600
- Removal of old back-boiler: £400–800
Manufacturer warranty periods vary significantly, Worcester Bosch and Vaillant accredited installers can offer 7–10 year warranties; non-accredited installers typically offer 2 years. The extra warranty from an accredited installer is usually worth choosing.
Heat pump costs in Wales
Air source heat pumps (ASHPs) are increasingly viable in Wales, particularly after the £7,500 Boiler Upgrade Scheme (BUS) grant.
Air source heat pump (supply and fit, before BUS grant):
- Smaller properties (up to 3-bed): £9,000–12,000
- Larger properties (4-bed+): £12,000–16,000
- Very large or rural properties: £14,000–20,000
After £7,500 BUS grant, net cost:
- Smaller properties: £1,500–4,500
- Larger properties: £4,500–8,500
Heat pump costs include the outdoor unit, indoor hydrobox or air handler, commissioning, and all pipework connections. They do not include insulation upgrades or new radiators, which may be needed, budget £500–3,000 for these if required.
Ground source heat pump (GSHP):
- £15,000–30,000+, significantly more expensive due to ground loop installation. Less common in Welsh residential properties.
Air conditioning costs
Air conditioning in Welsh homes is less common than in southern England but growing, particularly for home offices and bedrooms.
Single split air conditioning system (1 room, supply and fit):
- Budget brands: £1,200–1,800
- Mid-range (Mitsubishi Electric, Daikin, Fujitsu): £1,800–2,800
Multi-split system (3 rooms from 1 outdoor unit):
- Mid-range: £4,000–8,000
Ducted (concealed) system (whole house):
- £8,000–20,000
Air conditioning engineers in Wales must hold an F-Gas qualification to handle refrigerants, always check this certification when hiring.
Annual servicing costs
Regular servicing maintains efficiency, keeps warranties valid, and identifies safety issues early.
Annual boiler service:
- Cardiff, Newport, Swansea: £70–100
- Valleys and rural areas: £60–90
Air conditioning annual service:
- Single split system: £80–150
- Multi-split system: £120–250
Heat pump annual service:
- Air source: £100–200
- Ground source: £150–300
Landlord gas safety certificate (CP12):
- Per property (Cardiff, Swansea, Newport): £70–100
- Per property (Valleys, rural): £55–85
Annual servicing contracts typically offer discounts versus one-off service calls, most heating engineers offer plans at £80–180/year for a boiler service plan including priority call-out.