Should I replace my old back boiler with a combi boiler?

What is a back boiler?

A back boiler is a heating system that is fitted behind your fireplace. A rather outdated form of heating, these systems were used to provide heating and hot water.

If you currently have a back boiler installed into your home, it’s likely to be a Baxi Bermuda back boiler, a popular model in former times. Although these systems were popular in earlier periods, they began to fade out in the 80s when other boiler types were developed.

Are back boilers dangerous?

Although back boilers are not inherently dangerous, they are now an outdated and inefficient boiler system. They are no longer installed due to government safety regulations, and there have also been reports of explosions as a result of back boilers. This means in some cases they can be dangerous. They have also been known to cause structural damage to houses due to the expanding and contracting of the back boiler.

Here’s a list of the pros and cons of back boilers:

Pros:

• Built with fewer components
• Could be tucked away out of sight behind a fireplace

Cons:

• An outdated form of heating
• No longer energy-efficient in comparison to other boiler types (estimated to have efficiency ratings of under 80%)
• No longer installed
• Spare parts are very hard to find

Why should I replace my back boiler with a combi boiler?

From looking at the list above, it can be assumed that the cons outweigh the pros when it comes to back boilers. Combi, heat-only and system boilers are currently the main types of boiler systems used in the UK; combi boilers being the most popular.

What is a combi boiler?

Also known as combination boilers, combi boilers provide both heating and hot water all through one single unit. No additional water tanks or cylinders are required, so they occupy minimal space.

Combi boilers are also condensing, which means that they can recover and recycle latent heat through water vapour condensation – making them highly energy-efficient.

Pros and cons of combi boilers:

Pros:

• Space saving – they can be fitted into a standard kitchen cupboard
• Highly energy-efficient – it’s estimated that most combi boilers have an efficiency rating of over 90%
• On-demand hot-water
• No water tank or cylinder is required which could make water cleaner and safer to use
• Installation could be cheaper and easier due to there being less components
• All new combi boilers are condensing
• Part L of the building regulations require that all new combi boilers are installed with an additional energy-efficient measure such as a smart thermostat
• Replacing your old back boiler with an energy-efficient, A-rated combi boiler could help you save up to £200 on your annual energy bill*.

Cons:

• No backup immersion heater
• Water pressure can decline if more than one appliance requires hot water at the same time
• The system will not supply hot water to taps and radiators simultaneously.

What is the cost of replacing a back boiler?

Replacing your old back boiler with a combi boiler is likely to be an expensive job, estimated at anything from £3000 onwards.

Although this may seem to be a costly expense, you should bear in mind that there are potential savings to be made with a new and energy-efficient combi boiler. Not to mention the quality of heating and hot water that combi systems provide.

It’s likely that a back boiler removal will take quite a bit of uprooting as it is positioned behind your fireplace. Typically, the process will include:

• Removing the fireplace
• Removing the back boiler system
• Reconstruction of the mantle space
• Installation of the combi boiler system in an alternative location
• New pipework installed to fit with new combi boiler
• Work to be done on the flue system to suit the combi boiler (the back boiler would have used the chimney).

Installing a combi boiler

If you’d like to move forward and replace your old back boiler with a modern and energy-efficient combi boiler, HomeServe is now working with BOXT, one of the largest boiler installation companies in the UK, to help you get the right new boiler for your home.

BOXT’s expert advisors can provide you with answers to your questions and their Gas Safe registered engineers can conduct a professional installation of your new combi boiler.

Try BOXT’s free online quote tool today to get a fixed price quote for your new installation.

Get a new boiler 

*Source: energysavingtrust.org.uk. Saving calculated when replacing G-rated with A-rated boiler in a semi-detached house.