What is a Back Boiler: The Popular 90s Heating System


What is a back boiler? This question is quite among the new generation. While tech-savvy landlords from the 90s are all-too-familiar with this heating system, the craze for this heating system made it a must-have for every building.

But like every other technology, back boilers began to fade as the new competition came into play. However, those unfamiliar with this vintage heating system have questions like: are back boilers safe? What are they? And how do they work?

This article will answer all your back boiler-related questions and offer comparisons with more recent technology.

What is a Back Boiler?

Basement boiler system

Basement boiler system

Back boilers are home heating units placed behind a fireplace or gas fire system. So, they helped generate hot water and heating for the entire house. Also, the device was essential for maintaining a room’s temperature.

Interestingly, these units were present in most homes until the Government changed the Building Regulations in 2005. So, the changes made it compulsory to swap back boilers for high-efficiency condensing boilers. Although most building owners have made the switch, back boilers are still present in many UK homes.

How do Back Boilers Work?

The boiler system in a basement

The boiler system in a basement

Back boilers usually sit behind stoves or fireplaces. And they connect to hot water cylinders. Hence, they operate by using the heat created by fireplaces or stoves. Further, these units utilize this heat to provide central heating and hot water. Also, the entire system receives mains water via a cold water tank. 

Moreover, the heat generation process starts when the back boiler heats the mains water and stores it in the cylinder. Then, the system sends the hot water to showers, taps, and radiators.

In addition, back boilers have two primary types: wet-back and dry-back models. The rear wall design of these machines is what sets them apart.

Wetback boilers have rear walls surrounded by water, while dry-backs feature designs lined with refractory. However, we consider wetback boilers more efficient than their dry-back counterparts since the system uses combustion to heat water.

Are Back Boilers Illegal?

Man repairing a boiler

Man repairing a boiler

Although back boilers are still present in many homes, there have been no new installations since 2005. Installing back boilers is illegal due to their high carbon emissions and government safety regulations.

Also, the UK government declared that it’s illegal to use an old back boiler system. However, you can only keep your old back boiler in place after upgrading to a newer model.

What is the Difference between a Back Boiler and Combi Boiler?

Here are a few differences between the back boiler and its replacement (the combi boiler).

Back Boiler Vs. Combi Boiler: Efficiency

While less-expensive boilers are attractive offers, you shouldn’t focus on upfront costs alone. The total ownership cost, including energy, is one thing you must consider when deciding between the back and combi boilers.

The maximum efficiency a back boiler can reach is 80%. On the other hand, combi boilers boast up to 100%, making them the most energy-efficient units available. 

As a result, many homes are replacing the back boilers with combi models to enjoy reduced energy costs. Although combi boilers have a higher upfront cost, they offer more benefits in the long run.

Back Boiler Vs. Combi Boiler: Installation

Combi boilers are ideal replacements for back boilers because of their easy installation process. In short, back boilers were a bit more complex to install as they require more components than their combi counterparts.

Back Boiler Vs. Combi Boiler: Space

Combi boiler systems merge water heaters and central heating into one unit. So, they occupy less space than back boilers.

Also, they eliminate the need for separate cold and hot water tanks prevalent in back boilers. So, opting for combi systems allows heating without needing fume vents in the fireplace.

In addition, back boilers feature compact sizes, but combi boilers are upgraded models. So, the latter is ideal for small flats & homes. And they help to conserve more space that back boilers occupy in water cupboards or utility rooms.

Is a Back Boiler Worth It?

Back boilers are still illegal in 2022. Hence, they’re not worth the trouble. In addition, they have pitiful energy efficiency and high carbon emission.

Further, back boilers are challenging to fix and need frequent (and costly) maintenance. Unfortunately, most manufacturers don’t produce or have the required parts to fix these systems.

Back Boiler Replacement Costs

Two factors determine the cost of a back boiler replacement: the price of the new system upgrade and removing the old system. We estimate you’ll spend a minimum of £3,000 in total–if you’re upgrading to a combi boiler.

Alternatively, you can request decommissioning instead of removal to save costs. Interestingly, this process disconnects the boiler from its power and gas source. 

Decommissioning your back boilers could save approximately £1000 on your replacement costs. Other things that potentially affect boiler upgrade expenses include:

  • Re-piping system to a new area.
  • Extra components like cold water tanks and hot water cylinders.

Are there Removal Grants for Back Boilers?

Unfortunately, you can’t get any direct back boilers removal grants. However, you may apply for grants to upgrade your entire heating system.

Additionally, each grant has its eligibility criteria. So, back boilers are eligible for grants like the Boilers Upgrade Scheme and the ECO4 scheme.

Rounding up

Back boilers may have been the trending heating systems in the 90s, but now they’re nothing more than an environmental hazard. The U.K. banned the installation of back boilers in 2005, making them illegal.

However, many homes still have these boilers running. Sadly, all they get is high energy bills and less efficiency. We recommend upgrading your back boilers to more energy-efficient systems for a better heating experience.

Also, you may apply for grants to help with your upgrade plans if the costs are high or you want refunds.

Do you have more questions? Be sure to contact us, and we’ll be happy to help.

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