What is a high efficiency condensing boiler?

A high efficiency condensing boiler works on the principle of recovering as much as possible of the waste heat which is normally rejected to the atmosphere from the flue of a conventional (non-condensing) boiler. This is accomplished by using an extra-large heat exchanger or sometimes two heat exchangers within the boiler which maximises heat transfer from the burner as well as recovering useful heat which would normally be lost with the flue gases. When in condensing mode (for condensing boilers do not condense all the time) the flue gases give up their 'latent heat' which is then recovered by the heat exchanger within the boiler. As a result the temperature of the gases exiting the flue of a condensing boiler is typically 50-60°C compared with 120-180°C in a current non-condensing boiler. At the same time an amount of water or 'condensate' is produced.
A condensing boiler will always have a better operating efficiency than a conventional non-condensing one, due to its larger and more efficient heat exchanger.
Is your boiler energy efficient?If it's 10-15 years old then it probably isn't. Replacing your old boiler with a new high efficiency condensing boiler will save you around a third on your heating bills straight away.
If you're fitting a new kitchen or bathroom, why not minimise cost and disruption by installing a new high efficiency condensing boiler at the same time? By law most new gas boilers fitted in England and Wales must now be high efficiency condensing boilers (with a few exceptions depending on suitability). High efficiency condensing boilers can be easily fitted to most new and old heating systems, ask your installer for more details. And that's not all... If you install the right heating controls, you could save up to 40% on your fuel bill - that's about £190 - £240 off the average bill.Did you know?
If everyone in the UK with gas central heating installed a high efficiency boiler, we would save enough energy to heat 3.7 million homes for a year.