Over half the money you spend on energy each year is spent on heating and hot water – so upgrading your boiler to a more efficient model or system can make a huge difference to your bills.
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.
It is recommended that you upgrade your boiler around every 12 years – do you know how old your boiler is?
If it's time to change your boiler, or if you're thinking ahead for when it needs to be replaced, you will need to decide what type of heating system is right for you and your property. 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:
If you have a mains gas connection, a modern, condensing gas boiler has typically the lowest running costs to provide heating and hot water. On average, gas is currently the cheapest heating fuel per kWh, compared to oil, electricity, LPG and house coal.
If you are looking to lower your carbon emissions, you should perhaps consider a form of low carbon heating solutions such as a heat pump, which could also reduce your running costs depending on the type of system and fuel you're replacing it with.
Gas and oil boilers are either 'system' boilers, which have a separate hot water cylinder to store hot water, or 'combi' boilers, which heat hot water on demand and don't require a hot water cylinder.
A system boiler is more efficient than a combi boiler at producing hot water, however heat is lost from the hot water cylinder over time. A combi boiler can be more efficient overall, although this depends on several factors such as how many people there are in the property and whether you are likely to install solar panels in the future. Having a hot water cylinder allows you to store energy from a solar system - if you are not able to install solar panels then this might influence your decision.
Choosing the right boiler for you will depend on different things including:
Your hot water usage. Large families using lots of hot water are likely to be better off with a system boiler, whereas smaller households using less hot water may be better off with a combi boiler.
Space in your home. Combi boilers don't need hot water cylinders, and therefore require less space.
Compatibility with solar water heating. If you're thinking of installing solar water heating, it's simpler for them to work with system boilers, although combi boilers can be adapted too.
Being heat pump ready. Most heat pumps work with a hot water cylinder, so if you get rid of your existing cylinder and fit a combi boiler, keep in mind that the cylinder may need to be put back in if you switch to a heat pump in the future.
Replace a gas boiler
The cost of replacing a gas boiler will vary, but a typical replacement plus thermostatic radiator valves will cost about £4,000.
Replacing an oil boiler
The cost of replacing a oil boiler will vary, but a typical replacement plus thermostatic radiator valves will cost about £4,700.
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: