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.

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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 HomeCare 200™ 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.

* 91% recommendation rating is based on 1,463 customer responses collected between 09/12/2014 & 02/02/2015.

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

Quality of installation
Advice from Heating Adviser
Overall rating
Scores 8.8 out of 10 based on 2306 reviews
10 out of 10

Confirmed purchaser

A very professional service from start to finish, there was a small problem that developed about a week after the installation and was fixed immediately.
Published on: 04 March 2015
10 out of 10


The person carrying out the installation was friendly and helpful and made sure everything was working satisfactorily. He also tidied-up when he left with no mess. We were very pleased with service we received. Thank you.
Published on: 04 March 2015
9 out of 10


Though possibly a little on the higher side of cost, the product was fitted with care and attention, they were very tidy and indeed cleaned up after themselves well. the information and demonstration they did at the end was clear and easy to follow.
The follow up was also welcome and I would have to give 10 out of 10.
Published on: 03 March 2015
7 out of 10


Good service, quote given was detailed, all information correct and adhered to. Only issue was during installation some pipework was not connected correctly which led to water flowing through our wardrobe and only noticed when it came out of the kitchen light fitting!
Published on: 03 March 2015
10 out of 10


Very pleased with the advice and installation
Published on: 03 March 2015
8 out of 10


This is the first new boiler I have ever had to get fitted so it was a bit daunting with lots of companies undercutting each other but I saw 3 other companies and didn't feel comfortable with their offers or how they were going to do it and who made the final decisions. I went back to the first supplier to see if they could review their quote and they did. They were still the most expensive but I felt the extra cost now would be recouped in a better product, better installation and life of the product.

The first appointment had to be cancelled due to the planned engineer was in a car crash two days before due to arrive. The following week a new engineer arrived but the parts hadn't arrived the day before as planned so spent a lot of time chasing the parts and liaising with the engineer to see if he could still start the installation. The engineer was excellent , explained what would happen and when , allowed us to time to get water stored up to keep us all in hot drinks whilst the water and gas was off !!

The installation was carried out as planned and the electrician arrived the next day to complete the wiring , even with an issue getting the power feed to the new controls in the airing cupboard , between the engineer and the electrician they sorted out the best route and the neatest installation I could ask for.

Bricking up the old ugly flue was an excellent job by the engineer, taking out extra bricks first to make the new bricks fit better (no half bricks filling gaps) so it looks very neat and tidy.

Very pleased with installation but I wasn't around for the final explanation of the controls as I had to go back to work but should have been there as the controls are a little more complicated than the old ones and would like to have seen the engineer.

No follow up call as detailed in the brochure to check everything ok, so had to call home care back out as radiator valve was stuck on full on , making the room very hot.

The home care team came very quickly and fixed the problem.

Overall I am glad I went with this supplier and very happy with the install
Published on: 03 March 2015