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Heating your home

Boilers

Benefits

  • make your home more energy efficient
  • reduce your fuel bills
  • cut your household carbon footprint

Heating accounts for about 55% of what you spend in a year on energy bills, so an efficient boiler makes a big difference.

All well-maintained boilers burn their fuel very efficiently, but they inevitably lose some heat in the hot gases that escape up the flue (a pipe for extracting fumes and supplying fresh air to the boiler).

Modern boilers are more efficient for several reasons, but their main advantage is that they are all condensing boilers. A condensing boiler has a larger heat exchanger, so it recovers more heat, sends cooler gases up the flue and is more efficient.

Sometimes the flue gases get so cool that the water vapour in the gas condenses out, and even more energy is recovered from the condensing vapour.

Things to consider

If it is time to change your boiler, you need to decide what type of boiler is right for you. Here are some things to consider:

Improve your central heating system

It’s also worth considering whether you can improve your central heating system by making one or more adjustments to your heating. These include:

Heating controls

There is a wide range of heating controls available that will help your heating system work more efficiently and help keep your bills down. Find out which thermostats and controls might be appropriate for your system.

Heat recovery devices and systems

Some of the heat generated by your boiler escapes through the flue. Passive flue gas heat recovery systems capture some of this lost energy and use it to heat your water, making your heating system more efficient and saving you money. They are only available for combi boilers as they provide heat to the cold water supply that is feeding the hot water output.

Some models include heat storage, which increases the savings but usually increases the installation cost. Some new boilers are made with flue gas heat recovery already incorporated, so there is no need to buy a separate heat recovery device.

Hot water cylinders

New hot water cylinders are factory insulated to help keep your hot water at the right temperature for longer. They play an important role in supplying you with readily available hot water, so it’s important that they are fully insulated to prevent heat escaping.

If you have an old cylinder you could save around £20 a year by topping up the insulation to 80mm. Alternatively if you are replacing your cylinder, you can save energy by making sure the cylinder is no bigger than you need it.

Chemical inhibitors

Corrosion deposits in an older central heating system can cause a substantial reduction in the effectiveness of the radiators, and the system as a whole. The build-up of scale in heating circuits and on boiler components can cause a reduction in efficiency too.

Using an effective chemical inhibitor can decrease the corrosion rate and prevent the build-up of sludge and scale, thus preventing deterioration and helping to maintain efficiency.

Costs and savings

England, Scotland and Wales

Replacing a gas boiler

The costs for replacing a boiler will vary, but a straightforward gas boiler replacement plus thermostatic radiator valves will typically cost about £2,300, excluding radiators.

Northern Ireland

Replacing an oil boiler

The costs for replacing a boiler will vary, but a straightforward oil boiler replacement plus thermostatic radiator valves will typically cost about £3,100.

Finding an installer

For a list of registered installers visit the Competent Persons Register, SNIPEF, or Installers First.

For gas and LPG boilers, the installer must be Gas Safe registered. For oil boilers, we recommend that you use an OFTEC registered installer.

It’s worth getting three quotes from different installers, and you may also want to check that installers have:

  • a local office
  • been in business locally for several years
  • customer references that you can review.

Your registered installer will ensure that your system complies with current building regulations, and will make sure you get all the documentation to prove this. Keep these documents safe as you will need them when you sell the property.