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More than 80 per cent of home energy use is for heating and hot water, so getting a more energy efficient boiler can make a very big difference. Look out for the energy-saving recommended label when you′re choosing a new boiler - it can only be used on the most energy efficient products, usually the top 20 per cent of those available.

If everyone with gas central heating installed a high efficiency condensing boiler, we would save enough energy to heat millions of homes.

Using a high efficiency condensing boiler could save you up to 25% a year. This can also significantly cut your home′s CO2 emissions as boilers account for around 60 per cent of all domestic CO2 emissions.

As the current lifespan of a boiler is around 15 years, choosing a heating system with a high efficiency condensing boiler with the correct heating controls can make a huge difference to your heating bills over time. You could save a third on your heating bills by replacing your boiler.

Is your boiler energy efficient?

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. The best high efficiency condensing boilers convert more than 90% of their fuel into heat, compared to 78% for conventional types.

This is accomplished by using a larger 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 (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.

If your boiler is 10-15 years old then it probably isn′t. Replacing it with a new high efficiency condensing boiler can save you around a third on your heating bills straight away.

Boilers are rated according to their efficiency in converting fuel to heat as a percentage. In the UK this rating is called SEDBUK - Seasonal Efficiency of Domestic Boilers in the UK. SEDBUK ratings are from A to G, A-rated boilers being more than 90% efficient. Only A rated boilers - having efficiencies of over 90% carry the Energy Saving Recommended logo.

Compare the efficiency of different boilers at www.boilers.org.uk

Consider fitting a new high efficiency condensing boiler at the same time you′re fitting a new kitchen or bathroom, it will minimise cost and disruption.

If you install the right heating controls, you could save up to 40% on your fuel bill.

By law new gas boilers fitted in most countried 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.

Energy Efficiency Bands

As a simple guide to efficiency, a scheme has been created with SEDBUK efficiency bands assigned to boilers on an "A" to "G" scale. The band is shown in the database and may be used on product literature and labels, though there is no requirement for manufacturers to do so.

The scheme is temporary as it will be withdrawn when a new directive on boiler energy labelling is introduced.