Combi boiler

Boilers explained - 1:54

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Today’s boilers are far more efficient than older models and could save you money on your energy bills.

They use condensing technology, which recycles heat in the boiler’s exhaust gases to pre-heat cold water entering the boiler. This means they use fuel more efficiently and less heat is wasted through the boiler’s flue.

There are three main types of boiler and it’s important to pick the one that’s best for your home and needs.

The combination or combi boiler as it’s usually known, takes water directly from your mains supply and heats it up when you turn on your tap.

It can provide limitless hot water when you need it. However it can struggle to maintain a steady flow if multiple hot water taps are running at the same time.

Another option is the conventional boiler. It’s usually connected to a more traditional central heating system where the water is heated and stored in a hot water cylinder.

It can deliver hot water to multiple taps at once, making it a good choice for larger homes with more than one bathroom.

A system boiler works in a similar way to a conventional boiler, but comes with some key components built-in. It’s a great for homeowners after a bit of extra space.

Making the right choice is important, so one of our Heating Advisors will visit your home to help work out which boiler options is best for you.

They’ll carry out a survey of your home to asses your heating needs and give you a quote. If you’re happy with our quote, they can arrange an installation date that’s convenient for you.

Take a look through our website to learn more about our boilers.

You can get an estimate online or book an appointment with a Heating Adviser.

If you’re thinking about changing your boiler, it’s important to know the different types and how they work.

There are three main types of boiler to choose from:

If you’d like to find out more about the benefits of getting a new boiler or arrange a home assessment, book an appointment online now.

Types of boilers

Combi boilers

  • Get limitless hot water on demand.
  • No need for a cold water tank or hot water cylinder.
  • Ideal for smaller houses and apartments.

Combi boilers in more detail

Combi boiler

Conventional boilers

  • Can deliver hot water to multiple taps at once.
  • Includes a cold water tank and a hot water cylinder.
  • Ideal for larger homes with more than one bathroom.

Conventional boilers in more detail

Conventional boiler

System boilers

  • Similar to a conventional boiler.
  • Many key components are built into the boiler unit.
  • Ideal for larger homes looking to save space.

System boilers in more detail

System boiler

Help on boilers

Does your boiler need replacing?

Find out how much you could save with a new boiler.

We have a range of boilers to suit your home.

Worcester Bosch Group Vaillant Baxi

Boiler costs

Get an estimated cost for installing a new boiler.

Reasons to choose British Gas

Fixed price quote

We guarantee a fixed price

When our Heating Advisors quotes a price, we guarantee it won’t increase even if there’s unexpected work to do.

Boiler cost calculator

No deposit

Pay monthly with no upfront deposit

We could help you spread the cost over 3-10 years or you could choose to pay in full if you’d prefer.

Payment options

Your home is left clean and safe

Your home is left clean and safe

Our Engineers leave your home neat and tidy and will arrange the safe disposal of all waste.

Step by step guide

Free aftercare

Aftercare included

This offer includes a year's free aftercare which provides service and repair for your boiler, controls and central heating system for one year.

Latest offers

British Gas New Heating Limited is authorised and regulated by the Financial Conduct Authority for its consumer credit activities. Registered in England and Wales 6723244.

[1] This offer is valid until the 31st December 2015 and is available for domestic properties only (up to 40kW). It excludes warm air units. The 20% discount is off the cost of the boiler only and will be applied at point of sale on the basis that we install the boiler. You can't use this offer with another British Gas offer unless the offer states that it's ok.

[2] Mon-Fri 7:30am-8pm, Sat 8am-6pm, Sun 8:30am-5pm. Limited service applies during public holidays.

* 91% recommendation rating is based on 4,967 customer responses collected between 09/12/2014 & 15/06/2015.

91% of customers recommend British Gas boiler installations*. See below for more detail on how they rate it. Reevoo

British Gas Boiler Installation Service reviews verified by Reevoo

7,445 reviews

Reviews from: Sort by:
(9.0 out of 10)
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Scores 9.0 out of 10 based on 7445 reviews
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(10 out of 10)


very pleased with the service overall
3 of 7 people found this review helpful
Published on: 13 November 2015
(8 out of 10)


Teldord Homeowner
apparent problems with electric wiring resulted in further visits by an engineer.
2 of 4 people found this review helpful
Published on: 13 November 2015
(10 out of 10)


Coventry Homeowner
Really nice Guy. Quiet, clean, efficient and thoughtful.
If we have more work done would love him to come to do it
4 of 4 people found this review helpful
Published on: 10 November 2015
(9 out of 10)


Thurrock Homeowner
Work carried out expeditiously and professionally.
3 of 4 people found this review helpful
Published on: 09 November 2015
(10 out of 10)


Sudbury, Suffolk Homeowner
The new boiler installation went very smoothly with a minor 'hiccup' related to the new Hive Unit which was patiently and thoroughly sorted out by your technician. Great customer support over the phone, nothing seems too much of a problem :)
2 of 2 people found this review helpful
Published on: 09 November 2015
(9 out of 10)


Cannock Homeowner
Entirely satisfied with all work carried out.
4 of 4 people found this review helpful
Published on: 08 November 2015