Benefits
- Make your home more energy efficient
- Reduce your fuel bills
- Cut your household carbon footprint
Heatingand hot wateraccountsfor over halfof 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 pipeused to extractfumes and supply fresh air to the boiler).
Modern boilers are more efficientthan older boilersfor several reasons, but their main advantage is that they are‘condensing’. A condensing boilerrecoversmoreheat fromtheexhaustfluegasanduses it to heat the central heating water, making it moreefficientthan older boilers.
Things to consider
If it’s time to change your boiler,orifyou’rethinking aheadfor when it needsto bereplaced, you’llneed to decide what type ofheating systemis right for you. Now might be the righttimeto switch to a low or zerocarbonemission 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 considerwhen deciding what type of heating systemis right for you:
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If you have a mains gas connection, amodern, condensinggas boilerhas typically the lowest running costs to provide heating and hot water. Ouraverage fuel pricesshow gas to be the cheapest heating fuel per kWh, compared to oil,electricity,LPGand house coal.
If you’re looking to lower your carbon emissions, you should consider a form of low carbon heating such as a heat pump, which could also reduce your running costs depending on the type of system and fuel you’re replacing.
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Gas and oil boilersare either‘system’boilers,whichhave a separate hot water cylinder to store hot water, or‘combi’boilers,which heat hot water on demandand don’trequirea hot water cylinder.
See AlsoAre Oil Boilers Being Phased Out? – WundaOil Boiler Upgrade - Knowing When you Need OneWhat happens at a boiler serviceIs a Boiler Service Necessary?Asystemboiler is more efficient than a combiboilerat producing hot water,howeverheat is lost from the hot water cylinderover time. Acombiboilercouldbe more efficient overall,although this depends on several factorssuch 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 cylinderallows you to store energy from a solar system – if you are not able toinstall 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 asystemboiler, whereas smaller households using lesshot watermay 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 installingsolar 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 cylindermay need to be putback in if you switch to a heat pumpin the future.
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 orLPGboiler 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 whichthermostats and controlsmight 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,youcan choose a model withflue gas heat recovery incorporated into the design,or you can ask your installer to fit aseparate 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 £40 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 systemand the build-up of scale and sludge (rust)canreducethe effectiveness of the radiators, and theheatingsystem.
Using achemical inhibitorwilldecrease the corrosion rate and prevent the build-up of sludge and scale, thus helping to maintain efficiencyof the system.Inhibitors should be refreshedorreplaced whenever the heating system is drained during maintenance work or boiler replacement.
Filtration
Building regulationsencourage 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 filternear the boilerif 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 £3,700.
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 £5,500.
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 beGas Safe registered. For oil boilers, we recommend that you use anOFTEC registered installer.
Your registered installer will ensure that your system complies with current buildingregulations andwill make sure you get all the documentation to prove this. Keep these documents safe as you will need them when you sell the property.
Further reading
Heating controls
The right heating controls will let you keep your home at a comfortable temperature without wasting fuel or heat.
Blog How to control your central heating system
Do you know how to heat your home to a comfortable temperatureandkeep bills low?
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