If everyone with gas central heating installed a new condensing boiler we'd save over 13 million tonnes of carbon dioxide a year, as much as the annual emissions of over 2 million homes.

Boilers account for around 60% of all domestic carbon dioxide emissions. By fitting a new high efficiency condensing boiler with heating controls, you will significantly cut your home's CO2 emissions and could save around £200 a year.

Condensing boilers get their name because they condense periodically. In other words, they extract heat from the exhaust gases that would otherwise escape through the flue - turning water vapour from the gas back into liquid water or condensate.

A condensing boiler captures much more usable heat from its fuel than a non-condensing boiler. Its high operating efficiency is made possible by the design of the condensing boiler's larger - or sometimes dual - heat exchanger.

The heat exchanger makes sure that as much heat as possible is transferred from the boiler's burner - and as little as possible lost in gases through the flue.

There are two types of condensing boiler: regular and combination. Regular condensing boilers heat your hot water through a hot water cylinder. Combination condensing boilers give you instant hot water without the need for a cylinder. Please bear in mind that not all home heating systems will be compatible with a combination boiler. A qualified installer will tell you which type of condensing boiler, regular or combination, is most suitable for your home.

Is your boiler energy efficient?

If it's 10-15 years old then it probably isn't. Replacing your old boiler with a new condensing boiler can save you around a third on your heating bills straight away. Around 60% of CO2 emissions from your home are down to your boiler. With an efficient new boiler you could save up to 875kg of CO2 and £110 a year. Add in a full set of heating controls as well as a new boiler, and you will increase the savings to £190 - £230 and 1.7 tonnes of CO2 a year.

Heating controls

When it comes to heating your home efficiently - wasting as little fuel and heat as possible - then a full set of heating controls is just as essential as the right kind of boiler. Using heating controls correctly is the easiest way to keep your rooms at a comfortable temperature. And in doing so, they'll help to reduce your household's fuel bills and CO2 emissions, too.

In fact, fitting the correct heating controls could save you up to 17% of your heating bill. What's more, fitting a condensing boiler with a full set of heating controls could save up to 40% of your fuel bill: around £190 - £230 a year off the average bill. As their name implies, heating controls allow you to choose when the heating is on, how warm it is, and where you want the warmth. They will also make sure that the boiler is only turned on when it needs to be.

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 European directive on boiler energy labelling is introduced.