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Most common in the UK

Combi Boilers

Heats water on demand — no tank or cylinder needed

On-demand
No cylinder needed
Space-saving
Ideal for flats/smaller homes
A-rated
Most new combis are ErP A-rated

Pros

  • No hot water cylinder or loft tank required, saving space
  • Constant hot water on demand rather than a limited tank

Cons

  • Hot water flow rate can drop if multiple outlets run at once

About Combi Boilers

A combi (combination) boiler heats water directly from the mains when you turn on a tap, with no separate hot water cylinder or loft tank. That makes it the most space-efficient option and the most commonly installed type in UK homes, though very high simultaneous hot water demand (e.g. two showers running at once) can be a limitation compared to system or regular boilers.

How this works

1

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See if combi boilers suits your home

2

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3

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A Gas Safe registered partner installer gets in touch

Frequently asked questions

Is a combi boiler right for a larger household?

It can be, but if several bathrooms are used at the same time, a system or regular boiler with a cylinder may cope better with peak demand — worth discussing your household’s hot water usage with a Gas Safe registered installer.

Are you a boiler installer yourselves?

No — Best Boiler Deals is an independent comparison and information service. We recommend always checking an installer’s Gas Safe Register ID directly before any gas work begins.

Is all the pricing on this site guaranteed?

No — costs mentioned are typical ranges reported by trade sources, not fixed quotes. Always get itemised quotes from more than one Gas Safe registered installer before committing.

What happens after I request a quote?

A partner installer reviews your details and gets in touch to arrange a proper site survey — there’s no obligation to proceed with any quote.

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Overview above is honest general guidance, not a guaranteed quote. Installer-partner matching pending real network connection.