What is a condensing boiler?

Differences between new and old condensing boilers:

• Old condensing boilers use a different amount of useable heat they produce from the fuel it burns in comparison to new condensing boilers
• Old condensing boilers usually have a pilot light, which is burning all the time, despite whether the boiler is switched on or not
• A condensing boiler is more efficient than a non-condensing boiler, it has a much larger heat exchanger, which extracts over 90% of the heat from the fuel it burns, making it much more cost effective to run
• It extracts the heat from the flue gases, which would otherwise be lost to the atmosphere, and recycles the heat back into the heating system
• The water vapour in the flue gases can be so cool that it condenses (hence the name!), and is taken away to a waste pipe through a condensate pipe
• New condensing boilers do not need a pilot light burning all the time, because they fire up when there is a demand for heat, suing an electric spark.