How Does A Back Boiler Work?

How Does A Back Boiler Work

So you’ve heard of solar power, the latest energy resource that is supposed to be saving us all from global climate change. But what about back boilers? You might not know much about them, but they are one of the most important home heating systems in Europe and Asia.

The purpose of a back boiler is to capture heat from hot water so that it can be used elsewhere in the home. The system doesn’t use any electricity, so it doesn’t require anything other than a power source to get the water flowing.

Here is a basic overview on how they work.

How Does A Back Boiler Work?

If you have recently purchased a house or flat that has a back boiler, you might be wondering ‘how does a back boiler work?’.

A back boiler is a water vessel located in the roof space of your home. It is connected to your hot water tank via copper pipework and consists of a water container and a large copper cylinder, known as the ‘heat exchanger’, which is over 50 times the volume of your hot water storage tank.

To understand how a back boiler works, one must also understand how a traditional system works without a back boiler.

In this type of central heating system, cold water travels from the water mains to the hot water storage tank, which is usually situated in your kitchen or utility room. This process of heating the water takes about an hour.

Back boilers are an old-fashioned way to heat your home without burning wood or fossil fuels; their main ingredients are water and air (or steam). They work by transferring heat between two separate containers of liquid at different temperatures until one becomes hotter than the other. The hot liquid then flows through pipes into radiators where it heats up rooms for your comfort!

The system sounds simple enough if you know anything about heat. Let’s start at the source of your hot water, the boiler itself. Water is heated to create steam or hot air for homes. This is done by burning fuel in a combustion chamber that forces air into the system and then burns it with the gas coming out of another pipe. The fire heats up metal or ceramic bricks, which transfer the heat to surrounding water.

The fire heats up metal or ceramic bricks which transfer the heat to surrounding water. But before you let all of this steam go to waste, why not put it back into your house? Steam goes through a condenser and is cooled down through underground pipes until it reaches another boiler where it heats up again and the cycle continues until it is forced through a pipe into your home. The steam can also be directed to a hot water tank where you save energy for later use with a thermostat.

Back boilers are typically more efficient than other heating systems, as less fuel is required to warm up both the container and its surroundings. This makes them ideal for smaller homes without a great deal of insulation. They are also capable of heating water to a higher temperature than any other system, making it a popular choice in countries where the weather is cold and dry all year round.

Since back boilers have been around since just after the industrial revolution , they have been greatly improved with the advent of new technologies over time, including a sealed combustion chamber and condensers.

Are back boilers now illegal?

UK legislation prohibits the installation of back boilers as a sole means of central heating. There are three types of single-package systems outlined in the legislation, which are those that use electricity from a mains supply to power an electric or gas boiler.

These systems must also have an electrical input and be fitted with a standby boiler system for backup, so you will need a separate internal combustion engine unit to maintain your hot water supply once these single-package heaters have been installed for between 60 and 90 minutes.

The proposed new legislation says any consumer may request this type of heating at their own expense provided it has been installed by a competent installer using approved parts & materials. So what does this mean for homeowners?

It seems there is no credible alternative other than dual fuel system, so although it may be more cost-effective to opt for a “green” energy source such as solar panels, the reality is that consumers will need to become more inventive with their heating requirements.

So if you are still pondering what does a back boiler work , take heart because there’s light at the end of the tunnel!

Are back boilers expensive to run?

When considering which type of central heating best suits your needs, price should always be on top of your list. It’s also worth thinking about how much space and money you have available in your home and whether or not you want the hassle and expense of installing a new boiler.

For example, a combination boiler for your bathroom and kitchen will cost under £1,000, however if you want one for the entire home expect to pay around £2,500. Meanwhile back boilers , which offer an alternative form of condensing technology can be fitted by anyone with basic DIY skills and don’t require any special parts or materials; these can cost as little as £400.

Back boilers are now illegal in the UK, at least until another form of boiler is found to use instead. However, if you are interested in back boilers, you can search online for them and see what’s available. Keep in mind that they may be expensive to run because of their energy efficiency.

When installing a back boiler , you need to plan carefully and work around existing pipework. There are some things that would be more expensive to replace, such as your water tank or hot water cylinder, so talk about the future with an installer when you get in touch with them for a quote. It might not always be possible to install a back boiler , so you need to know the extent of the work involved before going ahead. A full, detailed quote will be necessary so you understand what you are paying for.

A back boiler is a type of central heating unit that has a large rear or back boiler as opposed to a conventional system with a small front-mounted one . The back boiler works along with your existing central heating system, usually by linking to the hot water tank of a standard combi boiler , but some models are dedicated back boilers.

Combining two boilers is an efficient way to heat homes from a central location, rather than having separate units in each room. The front-mounted unit takes care of hot water and heating in the smaller, adjacent rooms while the back boiler heats the rest of your house. This is particularly useful when you have larger homes or when you want to heat an entire floor rather than specific rooms.

How Does A Back Boiler Work

Does a back boiler heat radiators?

Yes, a back boiler heats radiators. In the simplest terms, a radiator differs from a convector in that it produces heat through air being forced through a pipe or tubes to the cooler radiators.

In order for this process to work, it is necessary for a back boiler to use water pressure to drive water through pipes to a radiator. The disadvantage of this type of heating system is that the home appliances have to be installed at ceiling level because water has to be pumped up into the system.

A back boiler is a heat storage device that is most commonly used in areas where space is limited. Unlike a conventional boiler, it does not have a water tank attached to the system. Instead, it has a large cylinder of water behind the radiators which absorbs heat from them and stores it.

In order for this process to work, a back boiler must have a certain amount of insulation between it and the outside air. If the heat from the radiator is not transferred into the water, then it will gradually escape into the room instead of being stored as energy. The system makes use of convection currents to ensure that this happens.

If you were to look at a cross-section of a back boiler, you would find that it has three layers. The first layer is the outer casing which separates the water from outside air. Surrounding this is an inner casing which separates the water used to heat the radiators and the water inside of them.

The third layer is located between these two casings and consists of thin metal sheets which separate the two casings without coming into direct contact with either of them. This acts as a barrier to help prevent heat loss.


A back boiler is a heat source that provides both central heating and domestic hot water. A typical installation consists of an oil or gas fired furnace in the basement or cellar, with pipes running up through the floor to supply heat into the home via radiators. Hot water circulates from this system around your house providing instant access for things such as washing clothes and making tea. The advantages of installing a back boiler are it’s efficient use of energy (so you can save on fuel costs), it saves space when compared to separate boilers and tankless systems, plus they’re environmentally friendly!

References : Risks from redundant solid fuel back boilers

Recent Posts