Combi vs system vs regular
Three boiler types, three different ways of heating your water. Here's the honest side-by-side, but only a Gas Safe installer who surveys your home can tell you which is right for it.
Get free quotesSide by side
| Combi | System | Regular | |
|---|---|---|---|
| Hot water | Heated on demand from the mains, no cylinder | Stored in a hot water cylinder | Stored in a cylinder, fed by loft tanks |
| Loft tanks | None needed | None needed | Required (feed and expansion tanks) |
| Multiple taps / showers at once | Can struggle, depends on mains pressure | Good, cylinder serves several outlets | Good, cylinder serves several outlets |
| Space needed | Smallest footprint, often just the boiler | Boiler plus an airing-cupboard cylinder | Boiler, cylinder and loft tanks |
| Typically suits | Flats, terraces, smaller homes with one bathroom | Busy family homes with 2+ bathrooms | Older or larger homes with traditional systems |
Not sure which you have?
No cylinder or loft tanks? Almost certainly a combi. A cylinder in the airing cupboard but no loft tanks points to a system boiler. Tanks in the loft plus a cylinder usually means a regular (heat-only) setup. If you're still unsure, pick "unknown" on the quote form, the installer will confirm at survey.
BoilerMatch UK introduces homeowners to local heating installers and you decide who, if anyone, you hire. We are not the Gas Safe Register, we do not fit or repair boilers ourselves, and any quote, work or warranty is agreed directly between you and the installer. This page is general information, not advice on what to buy, and not a statement about grants or funding.