Combi vs System vs Conventional Boiler

A system boiler works with a hot water cylinder (usually in an airing cupboard) but doesn't need a cold water tank in the loft. Most components are built into the boiler itself.

Pros: Can supply hot water to multiple taps and showers simultaneously, compatible with solar thermal panels, provides strong water pressure, and easier to install than conventional boilers.

Cons: Requires space for a hot water cylinder, hot water supply is limited by the cylinder size and can run out, and slightly more expensive than a combi to install.

Best for: Medium to large homes with 3 or more bedrooms and two or more bathrooms.

A conventional (regular) boiler works with both a hot water cylinder AND a cold water storage tank, usually located in the loft. Water is heated and stored in the cylinder until needed.

Pros: Suitable for homes with older heating systems, can supply large volumes of hot water, compatible with solar thermal, and works well in areas with low mains water pressure.

Cons: Requires the most space due to the cylinder and loft tank, most complex and expensive to install, and generally less energy efficient than combi or system boilers.

Best for: Large homes with existing conventional systems, especially where replacing the pipework would be costly or disruptive.

For most Birmingham homes, a combi boiler is the best choice — it's the most efficient, most compact, and most cost-effective option.

For larger homes with multiple bathrooms, a system boiler provides the hot water capacity you need without the complexity of a conventional system.

The best way to decide is to get a free, no-obligation assessment from Empower Gas. We'll assess your property size, hot water demand, existing pipework, and budget to recommend the right boiler type for your home.