Boiler installation, Combi boiler

Boiler Replacement Cost: How Much To Replace A Boiler?


Back-boilers are usually installed next to the fireplace in the house and can heat and supply hot water through the house without needing a traditional boiler to take up valuable space.

Back boilers have been manufactured since 1966 and are the most compact boilers available in the market. Back boilers were cheaper to buy and install when they first came to the market, so they were considered a good investment. Back boilers are popular in the UK, thanks to their simple design, build, and durability.

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Advantages of back boilers

  • Improved heating effectiveness of stoves by absorbing excessive or unwanted warmth.
  • Prevent the loss of heat from the flue system.
  • Oil-fed stoves with back boilers are highly efficient (up to 80%).
  • Cheaper to replace if you already have one.

Disadvantages of back boilers

  • Expensive to run and not very efficient as other modern boilers.
  • Difficult to install because of new building regulations.
  • High risk of leaking fumes into your premises.
  • It takes up valuable space as it is required to place a tank in the loft and a hot water cylinder in the airing cupboard.
  • Limited choice of the fire front.
  • It can be a little noisy.
  • The units are droughty and require a permanent air vent.

You will have three different options to be chosen if you have an old back boiler in your home and are thinking of upgrading. These options are as follows:

  • replace an old one with a more modern back boiler
  • replace an old one with a combi boiler

Keeping an old back boiler

Replacing with Baxi Bermuda BBU HE Back Boiler

baxi boiler logoBaxi Bermuda Back Boilers provide a ready-made solution and are the only boiler brand to release a modern condensing back boiler. Baxi Bermuda has revolutionized the replacement of old back boilers as there is no longer the need to relocate the boiler, which saves hundreds of pounds. It is also estimated that a Bermuda Back Boiler will reduce your annual bills by £235.

It is more efficient than the old one and has a SEDBUK A efficiency rating. Baxi Bermuda Back Boilers has a 15 KW heat output and has a room-sealed appliance removing the need for an air vent. The life of the Baxi Back Boiler is expected to be 10 years, which is less than an older, less technical back boiler.

The price of the new Baxi Bermuda BBU HE starts from around £1,000. Sometimes, there may be additional installation costs if it is required to install a new chimney liner or if it is difficult to access the boiler.  The common rule is that the cost of a back boiler installation is higher than the one for a combi boiler.

Replacing with a Combi Boiler

Combi_BoilersNowadays, many old back boilers are being with the combi boilers, which are more efficient than back boilers. A combi boiler heats a home`s hot water and provides central heating at the same time. Given that a combi boiler doesn`t have a hot water cylinder, it is a more compact unit, and therefore it helps save space.

Installation Costs of Combi Boilers

The Installation costs of a combi boiler are generally lower than installing a Baxi Bermuda Back Boiler because it hangs on the wall, making it a lot easier for a heating engineer to install one. A combi boiler installation will cost on average £500-£600; however prices can vary a little depending on the boiler model and whether you are replacing your radiators or not.

Combi Boiler Prices

The prices of combi boilers vary from £600 to £2,000 depending on the make and model of the combi boiler you will decide to go for. However, the total costs to invest in the supply and installation of a combi boiler will be on average from £1,200 up to £2,600.


Reliability: Combi boilers are less reliable than back boilers.

Durability: Combi boilers do not last as long as back boilers, so at some point, you will need to repair them extensively or replace them. Back boilers can last over 10 years if they are services property and regularly.

Need to replace or fix your back boiler? We can help!    Find a heating engineer

Keeping your old back boiler – Is it worth it?

An old back boiler is durable. It will last longer than the modern boiler, especially if the boiler has been serviced regularly. Simple technology means fewer problems. It won´t be as energy-efficient as the modern boiler. If you appreciate more durability than efficiency, keeping your old back boiler is the only option for you. In terms of prices and cost of savings, you will save your money in the long run.

Boiler Repairs

A back boiler, as well as other types of boilers, requires regular maintenance. Even back boilers are durable; there can be situations when you have to repair them. It is good to know that the government has set regulations requiring boilers to meet certain standards in energy efficiency. If your back boiler is still working efficiently and a technician has confirmed this, the new building regulations do not require you to have your back boiler replaced. The law allows you to keep your back boiler and buy spare parts to maintain it.

Some manufacturers are still producing spare parts for back boilers. The cost of engineer labor varies from £20 up to £50 per hour and the average time spent engineering will be 1-2 hours. There will be a broad selection of spare parts, which you can obtain. Here is the list for you of the most common spare parts and prices for them.

Boiler replacements cost

The prices include parts and estimated labor for installation:
– Boiler fan replacement will cost from £100 up to £300
– Boiler thermostat replacement will cost from £70 up to £1,000
– Boiler expansion tank replacement will cost from £200 up to £525
– Boiler tube replacement will cost from £70 up to £150
– Boiler gas valve replacement will cost from £50 up to £280
– Boiler timer replacement will cost from £70 up to £500
– Boiler zone valve replacement will cost from £10 up to £300

As you can see, the variation between these services is a lot. It is essential to ask for bids number of companies. Alternatively, you can use our network of tradespeople to get free estimates.

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