Combi boiler guides

Plain-English guides to buying, sizing and running a combi boiler.

CORGI Registered

On 1 April 2009 the Gas Safe Register replaced CORGI as the official gas registration body in England

A like-for-like combi swap typically costs £1,800–£3,000 fitted outside London. Here is what changes the price — and a calculator to estimate yours.

For a combi, size is about hot water demand, not radiators. Bathrooms and your mains water flow matter most.

Combis save space and money for most homes. System boilers win when several people need hot water at the same time.