How much does a regular boiler replacement cost in the UK in 2026?

A like-for-like regular boiler swap costs GBP 2,000 to GBP 4,500 all-in. The boiler itself is similar in cost to a combi (GBP 800 to GBP 1,800 unit), but install is typically 1-2 days because of the cylinder and loft tank pipework integration. Add GBP 700 to GBP 1,500 for a new cylinder if the existing one is over 15 years old. Replacing the loft cold tank adds GBP 300 to GBP 600.

Should I convert from a regular boiler to a combi?

Often yes for homes with 1-3 bedrooms and one bathroom. The conversion costs GBP 2,300 to GBP 4,000 including loft tank decommission, cylinder removal, and new pipework. Benefits: reclaimed cupboard + loft space, 5-10 percentage point efficiency gain, simpler controls. Not worth it for 4+ bed homes with multiple bathrooms or where the existing regular boiler system works well and isn't due replacement.

UK 2026 / May 2026

Regular boiler replacement cost

Q: What is a regular boiler?

Also called a heat-only or conventional boiler. It heats radiators directly and feeds a hot water cylinder which stores hot water for taps. Requires a cold water tank in the loft to feed both the cylinder and the cold water taps. The traditional UK domestic heating setup, common in homes built or extended before the mid-1990s. Less common in new builds since the rise of combi boilers in the early 2000s.

Also known as heat-only or conventional. UK 2026 like-for-like swap: GBP 2,000 to GBP 4,500 installed.

The three replacement paths

Like-for-like

GBP 2,000 - GBP 4,500

New regular boiler in the same spot. Keep cylinder + loft tank. 1-2 day install.

Convert to system

GBP 2,200 - GBP 4,200

Remove loft tank, keep cylinder (or upgrade to unvented Megaflo). Modernises the setup; reclaims loft space.

Convert to combi

GBP 2,300 - GBP 4,000

Remove cylinder + loft tank. Best for 1-3 bed, one bathroom. Reclaims cupboard + loft. 1.5-2 day install.

Top regular boiler models

Brand + model	kW range	Unit RRP	Warranty
Worcester Bosch Greenstar Ri	12, 15, 18, 24, 30 kW	GBP 1,000 - GBP 1,400	10 years
Vaillant ecoTEC Plus Regular	12, 15, 18, 24 kW	GBP 1,150 - GBP 1,650	10 years
Ideal Logic Max Heat	12, 15, 18, 24, 30 kW	GBP 800 - GBP 1,100	10 years
Baxi 600 Heat	12, 15, 18, 24 kW	GBP 850 - GBP 1,150	7 years

When to stay with regular vs convert

Stay with regular when

4+ bedrooms, 2+ bathrooms
Existing system is solid, just the boiler has failed
Loft tank and cylinder are under 15 years old
Solar thermal or future heat pump on the cards (cylinders integrate)

Convert to combi when

1-3 bedrooms, one bathroom
Mains pressure decent (over 1 bar; ideally 1.5+)
Loft / cupboard space is wanted back
Cylinder or loft tank also at end-of-life

Frequently asked

What is a regular boiler?

Also called heat-only or conventional. Heats radiators directly, feeds a hot water cylinder, fed by a loft cold water tank. Traditional UK setup found in pre-1990s homes.

How much is a regular boiler replacement?

GBP 2,000-GBP 4,500 like-for-like. Add GBP 700-GBP 1,500 cylinder replacement if needed, GBP 300-GBP 600 loft tank if replacing.

Is converting to combi worth it?

Yes for 1-3 bed homes with one bathroom. Worth it for the reclaimed loft + cupboard space and slight efficiency gain.

Can a regular boiler work with a heat pump in future?

Yes - heat pumps integrate with hot water cylinders. Combi-only homes need a tank added for heat pump compatibility, so a regular boiler with a good cylinder is closer to heat-pump-ready already.

See combi cost for the conversion option, or system cost for the modernisation route that keeps the cylinder.