System Boiler Replacement Cost UK 2026

A system boiler (with hot water cylinder) replacement in 2026 costs £2,400–£3,800 fitted. Best choice for larger homes with multiple bathrooms.

Quick answer

Typical UK price range: £2,400–£4,800. Typical time: 1–2 days.

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Boiler replacement calculator

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Boiler type Combi (like-for-like) System boiler Heat-only / conventional Combi with move

Region London South East South West Midlands North of England Scotland Wales Northern Ireland

Specification level Basic / standard Mid-range Premium / high-end

Extras

System power flush £350–£700 Magnetic filter £100–£200 Smart thermostat £200–£400 New TRVs (all rads) £250–£600 Flue extension £150–£350

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Budget Under £5,000 £5,000 – £15,000 £15,000 – £30,000 £30,000 – £60,000 £60,000+ Not sure

Timeline As soon as possible 1 – 3 months 3 – 6 months 6+ months Just researching

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Key points

• £2,400–£3,800 fitted
• Works with hot water cylinder (typically airing cupboard)
• Better than combi for 2+ bathroom homes
• Allows solar thermal integration

Cost breakdown

Item	Low	High
System boiler (supply)	£1,100	£2,200
Install labour	£600	£1,100
Power flush	£350	£700
Magnetic filter	£100	£200

Cost by UK region

Region	Typical cost
London	£4,860
South East	£4,500
South West	£3,960
Midlands	£3,600
North England	£3,240
Scotland	£3,420
Wales	£3,240

How to save money

• Pair with an unvented cylinder for best mains-pressure hot water
• Choose a Mitsubishi/Vaillant heat-pump-ready cylinder if planning a heat pump
• Solar thermal coil-in-cylinder is futureproof

How to find a trusted tradesperson

Get at least 3 quotes from vetted UK trade networks:

• Checkatrade
• MyBuilder
• Bark

FAQs

Combi vs system — which is better?

Combi for 1-bathroom homes. System for 2+ bathroom homes, especially if multiple showers might run together.

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Disclaimer: Prices are guide ranges based on 2026 UK market data. Get quotes from local tradespeople for accurate pricing.