Back Boilers with Gas Fires: Out of Use or Still on Top?

Follow us


A back boiler is a pretty small and compact heating unit usually placed at the back of an open fireplace hearth. Though its sizes are compact, this appliance is capable of satisfying all hot water and heating needs you have. It should also be noted that such models are very reliable and allow hot water to run from several taps without pressure loss.

back boilers with gas fires

Back boilers with gas fires were initially created in late 1960s and were extremely popular within 20 years after the very first appearance on the market.

Being hidden behind a chimney with a gas fire in front, such units provide pretty effective heating. They are usually made from cast iron, and they are a legacy, since the time the water was heated by a coal fire. With a pretty rapid appearance of smokeless zones and popularity of gas fires, it became very easy to fit such boilers.

At the very beginning of their use, back boilers with gas fires weren’t highly efficient. However, during the last years there have been made many various improvements that now allow them to replace other popular heating devices. Excellent reliability and efficiency of these appliances allows saving much money on eating bills and additional expenses.

Pros & Cons

As well as many other heating appliances, back boilers also have their advantages and drawbacks. Before getting such units, it is highly important to know about both sides of the medal.


  • reliable hot water and heating
  • hot water from several taps simultaneously, without affecting pressure
  • the unit is hidden
  • it is economical to upgrade/replace to a back boiler, in case you have an old one


  • can be expensive to run
  • the units are draughty and require a permanent air vent
  • they are a bit noisy
  • the choice of fire is limited

In addition to these cons and pros, there are some considerations to keep in mind. Usually back boilers with gas fires require much space, due to the fact there are a cylinder and two tanks. Besides, not every model may be easily referred to as highly efficient.

Boiler’s Structure

Normally, such boilers consist of a fire grate that carries the combustible material, as well as of a water chamber that surrounds it. The so-called water jacket is placed behind the fire, however, it may be at the sides or above the grate, having the flue passing through.

The heat input is gained from hot flue gases. The problem is that such units are too hard to drain completely. So, there are high chances that there is some residual water in the boiler. When heated it turns to steam.

They say that back boilers with gas fires have already fallen of use in the 21st century. Still there are some UK companies that keep advertising such units as perfect variants in cases of central heating systems replacement. They are available in clip-in and integral versions. The latter ones are usually installed at the factory during the stove manufacturing. They are more efficient and higher heat output appliances than clip-in ones that are sold as separate attachments to installed stoves.