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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 and hot water accounts for over half of what you spend in a year on energy bills, so an efficient boiler makes a big difference.

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

Modern boilers are more efficient than older boilers for several reasons, but their main advantage is that they are ‘condensing’. A condensing boiler recovers more heat from the exhaust flue gas and uses it to heat the central heating water, making it more efficient than older boilers.

Things to consider

If it’s time to change your boiler, or if you’re thinking ahead for when it needs to be replaced, you’ll need to decide what type of heating system is right for you. Now might be the right time to switch to a low or zero carbon emission heating system.

As part of the UK Government’s plan to reach net zero carbon emissions by 2050, fossil fuel heating systems are likely to be phased out over time. This will start with a ban on gas and oil boilers in new homes from 2025, and we expect to see more and more existing homes switch to a low carbon heating system, such as a heat pump.

There are several things to consider when deciding what type of heating system is right for you:

How to identify condensing boilers

Since 2005, virtually all gas boilers that have been fitted in the UK are more efficient, condensing boilers.

Your boiler will be a condensing boiler if:

  • The flue is made of plastic. If it’s made of metal, it’s unlikely to be a condensing boiler.
  • The boiler has a plastic pipe coming out of the bottom, through the wall and into a drain.
  • If it’s a gas or LPG boiler that was installed after 2005, or an oil boiler installed after 2007.

Improve your central heating system

It’s 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 keep your bills down. Find out which thermostats and controls might be appropriate for your system.

Heat recovery

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.

It’s not usually practical to fit a new flue gas heat recovery system to an existing boiler installation. However, if you are fitting a new boiler, you can choose a model with flue gas heat recovery incorporated into the design, or you can ask your installer to fit a separate heat recovery device along with the boiler.

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 £25 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 in an older central heating system and the build-up of scale and sludge (rust) can reduce the effectiveness of the radiators, and the heating system.

Using a chemical inhibitor will decrease the corrosion rate and prevent the build-up of sludge and scale, thus helping to maintain efficiency of the system. Inhibitors should be refreshed or replaced whenever the heating system is drained during maintenance work or boiler replacement.

Filtration

Building regulations encourage the use of magnetic filters to remove rust from the heating water. If your boiler is replaced, or swapped for another type of heating system, your plumber should fit a magnetic filter near the boiler if none is present.

Costs and savings

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 £2,500.

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 £3,200.

England, Scotland and Wales

Northern Ireland

Finding an installer

It’s worth getting three quotes from different installers to ensure you get the best value for money.

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

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.

Last updated: 26 November 2021