James Elston

James Elston

Published February 8, 2024

Are you considering replacing your outdated back boiler with a modern, energy-efficient heating system?

Look no further! In this expert guide, we’ll delve into the world of back boiler replacement, exploring the benefits, costs, and best practices for removing and upgrading your old heating system.

Say goodbye to inefficiency and hello to a cosy, cost-effective home!

Back Boiler Replacement Overview

  • Back boilers are outdated heating systems that have been replaced by modern, more efficient and safer models.
  • Removal of a back boiler must be done by certified professionals to ensure safety and efficiency standards are met.
  • Replacement costs typically range from £2,500 – £4,500 depending on local regulations & other factors.

What is a Back Boiler?

A back boiler is an outdated heating system that was typically installed behind fireplaces in older homes. These systems are less energy efficient compared to the modern boilers available today, such as combi boilers, system boilers, and regular boilers.

As a result, back boilers have been replaced by their modern counterparts, which offer increased energy efficiency and improved safety.

Back boilers fall short when compared to their modern counterparts due to their design and function, which significantly limits their energy efficiency and performance.

In fact, replacing a back boiler with a modern boiler can lead to considerable savings on heating costs and ensure uninterrupted access to heating and hot water, as many heating engineers may not have the expertise to repair back boilers.

For homeowners aiming to enhance their central heating system and cut down on energy expenses, switching to a modern combi boiler, system boiler, or regular boiler is a wise decision.

These modern boilers are designed to be more energy efficient, reliable, and environmentally friendly than their back boiler counterparts.

How Does a Back Boiler Work?

A back boiler heating system operates by harnessing heat from a gas or electric fireplace to heat water for central heating and hot water supply. The back boiler is connected to a central heating system through a hot water tank, providing warmth to taps and radiators in the home.

This unique design sets back boilers apart from other types of boilers, such as combi boilers, which are more common in modern homes and offer better energy efficiency.

Back boilers release their waste gases directly into the chimney, while modern boilers require a flue to expel boiler gases away from the building. This difference in waste gas management is just one of the factors contributing to the lower energy efficiency of back boilers compared to their modern counterparts.

Among the various heating systems available today, gas-condensing boilers are currently the most efficient option. These boilers can run at up to 90% energy efficiency, far surpassing the performance of back boilers and making them a popular choice for homeowners looking to upgrade their heating systems.

Back Boiler Removal

Removing a back boiler is a complex process that must be carried out by a certified professional to ensure safety and compliance with regulations.

A Gas Safe registered engineer will disconnect the pipes connected to the back boiler, typically located in the airing cupboard, and remove any unnecessary items and carpets from the vicinity to prevent damage from dirty water.

Once the back boiler is disconnected from the central heating system, the engineer will remove it from its location and, if necessary, reassemble the central heating system, ensuring that all fittings and pipes are properly connected for safety and compliance with regulations.

Engaging a Gas Safe registered heating engineer or installation business for the removal or decommissioning of the back boiler is necessary to ensure safety and efficiency.

Additionally, having the proper certifications, such as a Building Regulations Compliance Certificate, will ensure that your back boiler removal complies with all relevant safety standards.

How Messy is Removing a Back Boiler?

Removing a back boiler can be a messy and intricate process. Here are the steps involved:

  1. Remove the fireplace.
  2. Disconnect and remove the back boiler unit.
  3. Remove any associated pipes and fittings.
  4. Deconstruct the space where the back boiler was installed.
  5. Potentially redecorate the living space afterwards.

However, hiring a Gas Safe registered engineer can help mitigate the disruption and mess associated with back boiler removal.

These engineers implement several measures to reduce the mess during back boiler removal, including:

  • Protecting the surrounding area
  • Utilising dust control measures
  • Disposing of waste materials appropriately
  • Tidying up the work area afterwards

This ensures that your home is left in a clean and orderly state upon completion of the back boiler removal process.

To ensure the safe and efficient disposal of a back boiler, hiring a Gas Safe Registered heating engineer is of utmost importance. Many components of back boilers are recyclable, so contacting your local recycling centre or scrap metal yard to determine if they accept old boilers is a worthwhile endeavour.

Back Boiler Replacement

Replacing a back boiler with a modern combi, system, or regular boiler is an excellent long-term heating solution for your home, offering significant annual savings on heating costs. The boiler installation process, specifically for back boiler replacement, involves disconnecting the old back boiler from the central heating system, capping pipes, and dismantling components of the fireplace.

The benefits of back boiler replacement include enhanced energy efficiency, improved safety, and potential long-term cost savings. These modern boiler replacements are designed to be more energy-efficient and reliable than their back boiler counterparts, providing homeowners with a better heating solution.

Back boiler replacement costs can vary depending on the type of new boiler and installation fees. The cost of replacing a back boiler ranges from £2,500 to £4,500, depending on the type of new boiler, labour, and additional work required. Check out our guide on how much does a new boiler cost to learn more.

Homeowners aiming to enhance their central heating system and cut energy costs should consider upgrading to a regular boiler, system boiler, or combi boiler. These modern boilers are designed to be more energy-efficient, reliable, and environmentally friendly than their back boiler counterparts.

Back Boiler Replacement Cost

The back boiler replacement cost encompasses the following:

  • The installation of a new boiler, which will likely be situated in a distinct location
  • If a combi boiler is chosen, a hot water cylinder will no longer be necessary
  • The primary expenses associated with back boiler replacement are labour costs, the cost of removing the existing back boiler, and the cost of the new system being installed.

The cost of replacing a back boiler ranges from £2,500 to £4,500, depending on the type of new boiler, labour, and additional work required. These costs cover both the capping of the piping and back boiler removal, as well as the installation of the new boiler system.

Before embarking on a back boiler replacement project, consider the following factors:

  • Local regulations
  • Availability of skilled engineers
  • Selection of boiler and radiators
  • Overall impact of the central heating system on boiler efficiency

By taking these factors into account, you can make an informed decision about the best heating solution for your home.

Back Boiler to Combi Conversion

Converting a back boiler to a combi boiler is a popular option due to its increased energy efficiency and space-saving advantages despite the higher initial costs.

A back boiler to combi conversion involves replacing a back boiler with a combi boiler, which is a type of boiler that can supply hot water and central heating from the same unit without requiring an additional tank.

The benefits of converting to a combi boiler include:

  • Saving hundreds of pounds annually due to increased energy efficiency
  • Non-condensing back boilers only run at 70% efficiency, whereas condenser boilers can run at up to 90% efficiency
  • Hot water tanks can be removed from the airing cupboard
  • The new boiler can be situated in a kitchen or airing cupboard rather than behind the gas fire like the old back boiler

The expense of converting a back boiler to a combi boiler is considerably more than the initial costs. According to some manufacturers, the cost of replacing a back boiler with a combi boiler ranges from £2,500 to £4,500 and covers both the capping of the piping and back boiler removal.

You can research back boiler replacement costs even more by looking at multiple manufacturers. These boiler replacement costs may vary depending on the type of new boiler and installation fees.

Back Boiler Fireplace

After back boiler removal, the fireplace may require repairs or modifications to accommodate a new heating system or restore its original appearance. Common fireplace repairs necessary following the removal of a back boiler include:

  • Bricking up the revealed cavity in the chimney with concrete bricks or breeze blocks
  • Applying mortar and bonding for an even finish
  • Reconstructing the fireplace, mantle, and a significant portion of the floor beneath the boiler

The following steps should be taken to restore a fireplace to its original appearance after the removal of a back boiler:

  1. Remove the back boiler and disconnect any associated pipes and flue.
  2. Remove any newer bricks or materials covering the original fireplace.
  3. Insert a lintel at the appropriate height to support the structure above the fireplace opening.
  4. Restore the original brickwork or stonework of the fireplace.
  5. Repair or replace any damaged or missing parts of the fireplace, such as mantels or hearths.

It is recommended to consult with a professional fireplace installer or restoration expert for the best results.

Following the removal of a back boiler, a fireplace may potentially accommodate the following heating systems:

  • LPG condensing combi boiler
  • Electric fire
  • Bioethanol burner
  • Modern combi boiler
  • Regular boiler

This flexibility allows homeowners to choose the best heating solution for their specific needs and preferences.

Replace a Back Boiler – Final Thoughts

In conclusion, replacing a back boiler with a modern, energy-efficient heating system is an excellent investment for homeowners seeking improved energy efficiency, safety, and long-term cost savings.

Hopefully, we have provided valuable information on back boiler removal, replacement options, costs, and best practices. By upgrading your outdated back boiler, you can enjoy a cosy, cost-effective home and rest easy knowing that your heating system is working at its optimal efficiency.

Frequently Asked Questions

Are back boilers now illegal?

Given the potential risks, back boilers have been illegal to install since 2005 and should not be fitted. It is not illegal to have a back boiler that was installed before this law was implemented.

However, due to the poor efficiency and danger that back boilers present, back boiler replacements have become more and more popular among homeowners.

Is a back boiler a good idea?

Back boilers are incredibly inefficient when compared to modern combi boilers, with energy efficiency of only 70%, far below the government-mandated 86% minimum.

On top of this, a significant portion of the money you pay for heating is wasted due to back boilers relying on warmth from the fireplace to warm the water inside. For these reasons, it is not a good idea to use a back boiler.

What is a Baxi Bermuda Back Boiler?

When back boiler heating systems were legal and more common, the Baxi Bermuda back boiler was among the most popular choices. Compared to other boiler costs, the Baxi Bermuda was a more costly and durable option.

Despite this back boiler being one of the better choices to save money for homeowners, it still wasn’t an energy-efficient boiler compared to more modern systems. When you replace your back boiler and opt for a combi boiler, you gain a much more efficient heating system.

How much does a back boiler cost?

The cost to remove a back boiler alone ranges from £950-£1,600, while a complete replacement of the back boiler and central heating system will range from £2,800-£4,700.

Are there any grants available for back boiler removal?

Unfortunately, there are no grants specifically for back boiler removal. However, homeowners may be eligible for a grant to upgrade their heating system.

What is the alternative to replacing a back boiler with another back boiler?

A suitable alternative to replacing a back boiler is installing a new gas boiler, offering a modern and efficient option.

James Elston

James Elston

Boiler Expert


James Elston is the top boiler replacement and heating expert at Eco Happy. He has over 20 years of experience in the industry, focusing on Gas Safe boiler installations and offering home-heating and energy-saving solutions to homeowners across the UK. From sourcing the most energy-efficient combi boiler to providing specialist heating advice, James ensures that Eco Happy maintains the highest standards and best customer service.

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