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Blog Post 6 January 2021 Updated 8 February 2021

A quick guide to boilers

Did you know that heating accounts for over half of your household energy bill? An efficient boiler can make a big difference.

Modern boilers are generally condensing boilers, which makes them more efficient than older models. A condensing boiler has a larger heat exchanger, which helps it to recover more heat and stops hot gases from escaping up the flue pipe.

If you think it’s time to replace your boiler, it’s worth considering whether a low carbon heating solution could work for you. Technologies including air source or ground source heat pumps and solar water heating systems could help you reduce your energy bills and lower your household carbon footprint.

However, if renewable heating isn’t right for your home, our quick guide will help you decide what type of boiler you need.

Check your fuel type

If you’re connected to the gas mains, a gas boiler will probably be your cheapest heating option. Average fuel prices show gas to be the cheapest heating fuel per kWh, compared to oil, Economy 7, liquified petroleum gas (LPG) and coal.

If you don’t have a gas supply, consider installing low carbon heating, such an air source or ground source heat pump. You may even be eligible to receive payments for installing renewable heating through the UK Government’s Renewable Heat Incentive scheme.

Choose the right boiler

There are two main types of boiler: a regular boiler and a combination – or combi – boiler.

A regular boiler has a separate hot water cylinder that stores hot water, instead of providing it directly from the boiler. This makes it more efficient than a combi boiler at producing hot water, but some heat is lost from the hot water cylinder. This could make a combi boiler, which doesn’t need a cylinder, more efficient overall.

The right boiler for your household will depend on several factors. Smaller households using less hot water every day may be better off installing a combi boiler, and they also require less space than a regular boiler. However, if you’re considering installing solar water heating, many combi boilers are incompatible with this type of heating system.

Improve your heating system

Before you replace your boiler, it might be worth considering making one or more adjustments to your central heating system.

There’s a wide range of heating controls available to help your heating system work more efficiently and reduce your energy bills. Find out more in our advice on thermostats and heating controls.

If you have an old hot water cylinder, consider topping up the insulation to 80mm – this could save you around £20 a year on your bills, as the insulation prevents heat from escaping from the cylinder. Or, if you need to replace the cylinder, make sure you only buy the size you need.

It may also be worth looking into chemical inhibitors. Corrosion deposits can build up in older systems, impacting the effectiveness of the radiators and the system overall. Chemical inhibitors limit the corrosion rate, preventing the build-up of sludge and scale and helping to keep your system working efficiently.

Find an installer

If you do decide to replace your boiler, you should get at least three quotes from different installers. You can find a list of registered installers on the following websites:

For gas and LPG boilers, the installer must be registered with Gas Safe. 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 provide you with the documentation to prove this.

And remember, your boiler should be serviced once every 12 months to keep it running smoothly and safely throughout the year.

Last updated: 8 February 2021