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Boiler Advice

Back Boiler Replacement, BBU Removal and Conversion Costs

Back Boiler Replacement, BBU Removal and Conversion Costs

If you have a back boiler, you are probably aware that you can’t replace it with another one as replacing a back boiler with a back boiler is illegal due to its inefficiency and risk of carbon monoxide.

The cost to run a back boiler these days with the huge rise in gas prices is extortionate so a combi boiler conversion will likely be the best option.

You can get a fixed price online for a full back boiler to combi boiler conversion at fixed price with Easy Boilers.

This includes the removal of the back boiler and a brand new A-rated energy efficiency combi boiler or system boiler.

Back boiler replacement – What are your options?

When replacing a back boiler the only thing that you can’t do is replace it with another back boiler.

Replacing a back boiler with another back boiler is illegal, and they are no longer available to buy therefore you need to consider changing or converting as it is better known to a new gas boiler such as a combi boiler, system boiler or conventional boiler.

This ensures that you get a new gas boiler installation with condensing technology that runs at up to 94% energy efficiency.

Get new boiler quotes online>

Back boiler to combi conversion can be costly but worth it

Back boiler replacement isn’t a quick job, it can take a couple of days to do, but the end result of a new economical combi boiler can save you plenty of money in the long run.

If you need something larger due to high hot water demand or a large home, then there are other condensing boilers to choose from. The best thing is that the amount of money you can save converting your back boiler is quite considerable.

A non condensing back boiler only runs at 70% energy efficiency, therefore for every £100 you spend on fuel, only £70 of it is actually spent on heating your home, and the rest just goes up in smoke!

How much does it cost to replace a back boiler?

The cost of replacing a back boiler is between £2,500 and £4,500, depending on which boiler you choose and where to install your new boiler.

Back boiler replacement costs so much because you have to thoroughly remove the back boiler and install a completely different boiler elsewhere in your home.

The most popular boiler replacement is the modern combi boiler which is far more efficient and this compact boiler can fit in a kitchen cupboard.

What are back boiler heating systems?

Back boiler heating systems are usually a fireplace in your living room or basement powered by gas.

These visible gas fires are linked up to your central heating system via a large hot water tank at the back of your fire and pump hot water around your home to taps and radiators.

How do back boilers work?

A back boiler heating system is very inefficient but was very popular in the early 1960s when it was the latest innovation in heating homes, much like the combi boiler is today.

Back then, they will of been the most efficient way to heat your home. Now the most efficient is a gas condensing boiler.

Are back boilers illegal?

Back boilers themselves aren’t illegal, but it is to replace a back boiler with another back boiler. You would struggle, however, as there are no more being manufactured, and the ones that are more recently, such as the Baxi Bermuda back boiler, parts are starting to become less and less available.

This is also another reason to consider a new gas boiler.

Changing a back boiler to a combi boiler – save money in the long term

If your back boiler has decided to break down or you have had enough of overpaying on your gas bills, then changing your back boiler to another boiler is a cost-effective way to save you money in the long term.

Converting back boiler to combi boiler

Combi boilers are the most popular type of back boiler replacement due to the ease of installation and energy efficiency.

Changing or converting to a combi boiler can save you hundreds of pounds every year due to being much more energy-efficient. Although the initial cost of replacement is high, the long-term savings will far outweigh this and make it worth your while.

Costs involved in replacing a back boiler

As we have pointed out, replacing a back boiler isn’t cheap, but let’s look at the actual costs and what you will be paying.

We will cover the new boiler replacement costs, labour costs, back boiler removal costs, moving the boiler location & decommissioning, plus any extras. If you are changing to a combi boiler then you will likely want the hot water tank in your airing cupboard removed. This is also a good and very popular choice of place to put a combi boiler too when converting.

Back boiler removal costs

Removing a back boiler costs between £500 and £900 depending on the type of back boiler you have. The larger the old back boiler, the longer it will take to remove.

You must have your back boiler removed when you install a new boiler. This is an untidy job, and you will be left with an empty space where the boiler was as a new boiler cannot be installed in the same place.

How messy is removing a back boiler

Removing a back boiler is quite a messy job. The old boiler will be completely ripped out, and pipework will be removed and capped. As you can imagine, due to the work involved and the intricate nature of safely removing a back boiler, it can take a couple of days at least.

A qualified Gas Safe registered heating engineer should keep this mess to a minimum and not leave any visible pipework. If you are converting to a combi boiler, you can also have your hot water tanks removed too from your airing cupboard.

Back boiler replacement labour costs

Labour costs for replacing a back boiler are between £1,500 and £2,000. This is down to the amount of time it takes. Removing and replacing a back boiler can take up to 3 days.

This is compared to a simple combi boiler replacement that can take less than a day.

Sometimes if you want the job done quicker, it can take two engineers to complete the work. This would save time but not money as you would be paying for the same amount of labour.

Back boiler replacement price guide including removal, labour and a new boiler

Back Boiler Removal£500-£900
New boiler£500-£2,000
Labour costs£1,500-£2,000

Cost of replacing a back boiler with a combi boiler- the best option for long-term cost saving

A new combi boiler on its own costs between £500 and £2,000 depending on which make and model you choose.

The main thing to decide upon when choosing a new combi boiler is to ensure that it is suitable for your home.

If you have a large home with high hot water demand and a large central heating system then you may want to consider a system boiler.

The new boiler cost is about the same.

Replacing back boilers with a system boiler or regular boiler

If you have a large home with high hot water demand then a combi boiler may not be the best for you. If you have a back boiler, you may already have a hot water cylinder used to store hot water.

System boilers and regular boilers work similar, so if the hot water tank is usable you could install one of these types of boilers instead.

Removing back boilers for modern boilers

Modern boilers are gas condensing boilers. This means that they are at least 90% efficient. The condensing part of the boiler ensures that any waste fuel is recirculated back around the condensing boiler to be used up.

A modern boiler will have an energy efficiency rating of A or above. A back boiler efficiency rating would be below G, the lowest rating possible.

How much can you save changing from a back boiler to a gas condensing boiler?

It is estimated that if you change an old inefficient boiler to a combi boiler you can save up to £350 per year on your energy bills.

If you take the cost of the boiler installation into account at around £3,000, you will have made your money back in around eight years.

This may sound like a long time, but considering that you may have been paying £350 extra for eight years you could have wasted £3,000.

Full central heating and back boiler replacement cost

Back boilers are old, so your whole central heating system may also be old too. If you are replacing a back boiler, it may be a good idea to replace some of your central heating systems.

If you are replacing your back boiler with a combi boiler, you may want to make sure that the rest of your radiators and pipework are also brought up to date.

The actual cost of replacing the entire central heating system will also depend on the size of your home.

Cost of replacing a back boiler & central heating system with 6 to 8 radiators

This work will cost between £4,000 and £5,000 depending on which boiler you choose and which types of radiators you want in your home.

It also considers that you are just leaving the radiators where they are and replacing them with new ones. If you want to move radiators too, expect higher costs.

Can I keep my back boiler instead of replacing it?

Yes, if your back boiler is working perfectly fine, you can keep it.

If a back boiler is looked after properly, it can be used for as long as it works properly. The only downside is the running costs, but if you are not bothered about this, there is no real reason to change.

If you want a smart thermostat, you need to change boilers.

Can I get a new back boiler, or are back boilers now illegal?

Having a back boiler isn’t illegal, but replacing a back boiler with another back boiler is. The good thing is you can’t make this mistake as no more back boilers are being manufactured.

You have to choose a condensing boiler instead.

Back boilers are becoming rarer and rarer so getting hold of one is almost impossible.

Back boiler conversion to combi boiler installation Prices

If you are considering converting your back boiler to a combi boiler, you want to ensure that you get the best new boiler installation deals.

The cost will be quite high wherever you get your quotes from due to the labour costs and other costs we have mentioned, but you can get some good deals.

You can even spread the cost with boilers on finance.

Back boiler replacement quotes online.

You can now get back boiler replacement quotes online in under a minute with companies such as Easy Boilers.

They have an online boiler quote calculator with the option to replace your back boiler with a combi boiler, system boiler or conventional boiler.

You can choose our new A-rated gas boilers for all the boilers, including the complete removal of a back boiler and new boiler installation.


How do back boilers compare in terms of energy efficiency and safety with modern boiler options?

Back boilers, while once popular, are now considered inefficient and pose risks of carbon monoxide. The best replacement option is to convert to a modern boiler system like a combi, system, or conventional boiler.

Are there any specific guidelines homeowners should consider when replacing a back boiler with a modern boiler?

The cost of replacing a back boiler varies based on factors such as the type of boiler chosen, installation requirements, and labour costs. Generally, it ranges between £2,500 to £4,500, including removal of the back boiler and installation of a new boiler.

What factors should I take into account when deciding between different types of modern boilers as replacements for their back boilers?

When replacing a back boiler, homeowners should consider several factors to choose the most suitable modern boiler type. Firstly, prioritise energy efficiency by choosing for boilers with high ratings, such as condensing boilers labelled with an A-grade rating.

Next, assess the household’s hot water demand to determine whether a combi boiler for smaller homes or a system boiler with a hot water cylinder for larger households is more appropriate. Consider the available space for installation, as combi boilers are compact and ideal for homes with limited space. Compare installation costs, including labour and additional components, to find the most cost-effective option.

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