Back What is a Condensing Boiler?

A ‘condensing boiler’ is a class of highly efficient gas boiler. This covers modern combi-boilers, system boilers and regular boilers.

Since condenser boilers are ultra-efficient, councils and housing associations across the UK only install condenser boilers in the homes they manage.

Indeed since 2005 the Building Regulations require all new homes be equipped with a condensing boiler.

This requirement now applies across the entire Euro zone.


How condensing boilers work

Condensing boilers efficiently use the heat that is generated. When water is heated some of that heat escapes via the flue. However a condenser boiler recycles heat omitted through steam. Steam heat is used to heat water returning into the boiler through the central heating system. A condensing boiler thus requires less heat from the central burner. This in turn saves you money on your gas bill.

Whilst a non-condensing boiler draws air from the room, a condensing boiler is completely sealed. This prevents warm air from escaping the system. This warm air is used to re-heat water that circulates around your home. This feature means condensing boilers are around 30% more efficient than non-condensing boilers. The Government estimates that condensing boilers will save the home owner around £340 on his or her fuel bill each year. Non-condensing boilers may be as low as 60% efficient. This means for each £100 you spend on fuel, £40 is lost to the outside world without you feeling the benefit!

Steam is not able to escape through a condensing boiler’s flue due to sealing. Water on the flue may condense into water. To prevent the build up of water this water is removed through a ‘condensate’ pipe (and hence the name ‘condensing boiler’).

Unlike a non-condensing boiler, a condensing boiler does not require a continuously burning pilot light.

Condensing boilers are available for many different fuel sources as well as traditional gas. This includes solid fuel, oil and LPG.


How much money will I save by investing in a condensing boiler?

The exact amount of money you will save on your heating bill by virtue of installing a condensing boiler really does depend on the efficiency of your current boiler.

Please see the table below to determine how much you may save on your heating bill each year by choosing to invest in a condensing boiler:

The above chart is valid as of September 2015.