Boiler replacement cost: like-for-like vs converting

Like-for-like is the cheap option

Swapping a combi for a new combi in the same position is the simplest job we do: old boiler out, new boiler in, flue checked, system flushed, commissioned. From our fitted catalogue that starts at £2,415 including VAT.

Converting costs more — sometimes worth it

Taking out a heat-only or system boiler with a cylinder and tanks, and fitting a combi, means removing the cylinder, capping or removing the loft tanks, re-piping and often upgrading the gas run. Expect the conversion to add meaningfully to a like-for-like figure — the survey prices it exactly before you commit.

• Worth converting: you want the airing cupboard and loft space back, and your hot water demand suits a combi
• Keep the cylinder: two or more bathrooms running at once, or a large household — a system boiler copes better

Repair or replace?

A repair makes sense on a young boiler with a cheap part. Once a boiler is past ten years and the heat exchanger or PCB fails, the repair bill often approaches a third of a new boiler — on a unit with no warranty left. That is the point where replacement usually wins.

When to replace before it fails

• Repeated breakdowns in consecutive winters
• Parts becoming obsolete or long-lead
• Rising gas use with the same habits
• The warranty has expired and a major component has failed