Your boiler accounts for more than half of what you spend on energy, which means that an efficient replacement boiler can make a big difference to your energy bills.

Why renew your boiler?

Replacing an old gas boiler with a more efficient one and improving your heating controls could significantly cut your carbon dioxide emissions and save you money. Modern, condensing boilers are more efficient. They have a bigger heat exchanger and are able to recover more heat, sending cooler gases up the flue.

The flue gases can get so cool that they come out as water vapour, which makes the system even more efficient as further energy is recovered from condensing vapour. High efficiency condensing boilers convert more than 88% of their fuel into heat by recovering the maximum waste heat which a conventional boiler would send up the flue.

How much could I save?

Your savings will depend on the age of your current boiler and how inefficient it is. According to the Energy Saving Trust, your boiler is unlikely to be energy efficient if it is more than 10 years old.
Replacing your old boiler with a new, high-efficiency, condensing model will save you around a third on your heating bills straight away. The costs for replacing a boiler will also vary, however the figures below are estimated based on a new A-rated condensing boiler and full set of heating controls in a gas-heated, semi-detached home with three bedrooms.

 Boiler Table

Which options are available?

There are several choices to be made when installing a new boiler. A home energy assessment will look at all of the available options and make recommendations based on what is best for your home.

The options include looking at the type of fuel. If you have mains gas, a gas boiler is usually the cheapest option for you. If you currently have an oil, LPG or coal boiler then the feasibility of getting a mains gas connection to your home would need to be investigated. A wood-fuelled or biomass boiler or another type of renewable heating may also be worth considering. Although the installation costs can be higher, the savings could be up to £630 per year.

The next consideration is the boiler itself and whether a combination or heat-only boiler would most be most suitable for your home and the way you use it. Which option is best for you is dependent on how much hot water you use, how much space you have and whether you are thinking of installing solar water heating.

Combination boilers require less space, can provide a continuous flow of hot water and avoid heating water unnecessarily.  However, they are not compatible with solar water heating and are less suitable for houses where there are simultaneous multiple demands on the water, for example, if your home has several bathrooms. Conventional heat-only systems are able to provide hot water to several sources at once and are more suitable for larger houses. They do, however, take up more space than a combination boiler and some heat is lost from the hot water cylinder so they may be less efficient.

Your assessor will take all of this into consideration during a home energy assessment and will be able to advise you which boiler is best for your property.