Boilers Explained

Back boilers

Back boilers

Although no longer the first choice for customers in the market for a new boiler, some homes do still have a back boiler hidden behind their chimney, and if you are still using this system, installing a new model - or even a new type of boiler - could save you loads on your heating bills.


How back boilers work

Back boilers are generally no longer installed unless it is too complicated or too expensive to install a condensing boiler.

They are hidden behind the chimney in your home, with a gas fire front to cover them. Although they are usually a reliable type of boiler, they typically have an efficiency rating of only 78%, whereas new, condensing boilers are usually more than 92% efficient - not only better for the environment, but also easier on your pocket.

Back boilers are “open flued” which means that there must be an open vent to allow fresh air in to replace the fumes that go up the flue. This means that if a fault develops with the ventilation, flue or boiler itself, potentially lethal gasses can be released.

Advantages of back boilers

  • Could be cheaper to replace if you already have this system
  • Reliable - reducing the risk of a breakdown
  • Space saving if you already have one as it’s hidden behind your gas fire

Disadvantages of back boilers

  • Expensive to run and inefficient - with an average of only 78% efficiency
  • New building regulations make it difficult to install a new back boiler due to poor efficiency
  • Open flue means higher risk of fumes leaking into your home
  • Space hungry - two tanks are required in the loft and a hot water storage cylinder in the airing cupboard
  • Limited choice of fire front
  • Draughty and noisy


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