When it comes to energy bills, heating plays a large role in the annual cost and accounts for over 55% of your total domestic bill. That’s exactly why replacement boilers make a huge difference to your expenditure and there’s the potential to save over £300 each year.

Replacing your boiler

Modern boilers are typically condensing, which is why they hold efficient qualities. An older, well maintained boiler can burn fuel efficiently, however a lot of heat is lost in the flue. Condensing boilers have a larger heat exchanger, so they recover more heat and only allow cooler gas to escape.

This cool gas can cause water vapour (condensation), which is why condensing boilers are named so. Further energy can be recovered from the vapour so efficiency levels are even higher.

If you want to save more money on your heating bills, switching to gas will be a cheaper option if possible. Electric and oil fuelled boilers typically cost much more to run.

There are a few types of boiler to consider. Older boilers tend to store water in a tank in the loft or airing cupboard, whereas combination (combi) boilers can provide hot water directly and fit on the wall or in a kitchen cupboard. A combi boiler is your most efficient option, but won’t be suitable for everyone.

Old Boiler Rating Semi Detached Home Detached Home Bungalow Mid Terrace Home Mid Floor Flat
G £305 £490 £275 £250 £130
F £230 £365 £205 £185 £95
E £190 £310 £170 £155 £75
D £160 £255 £140 £130 £60

Thermostats & controls

Whilst replacing your boiler will significantly increase energy efficiency, you should also consider the thermostats and controls in your home. With the right controls for your home’s heating you’ll enjoy a more comfortable home without wasting fuel.

For those with electric storage heaters it makes sense to charge them up overnight during off-peak times, and then distribute heat evenly throughout the day.

If you’re on gas though, you’ll want to have control over the boiler with a thermostat, timer or programmer. You can even invest in individual room thermostats and thermostatic radiator valves (TRVs).

Boilers of any age can be programmed with specific controls and with these you can heat up only the room you’re using, whilst setting dedicated times for your heating or hot water to come on.

There are superb savings to be made as well and a typical three-bedroomed semi detached property could save between £70 and £150 every year.

If you already have controls fitted for your boiler, also consider turning the temperature down by just one degree. The Energy Saving Trust say this could reduce your bills by £75 each year whilst cutting carbon emissions by 310kg.

Boiler controls can be fitted without upgrading your full central heating, although of course it’d be cheaper to replace the boiler at the same time. This is especially the case if you have an aging boiler, particularly over 15-years-old.

Boiler jackets and pipe insulation

By investing in pipe insulation and lagging, you’ll help to reduce heat loss and ensure hot water stays hot for a longer period of time. Out of all the options for improving energy efficiency outlined in this guide, insulating the hot water cylinder and surrounding pipes is by far the easiest.

Your water tank may already have a jacket, but you’ll want it to be a thickness of at least 75mm. With one in place, heat loss from the water tank is reduced by 75% and you could save between £20 and £35 annually. Considering the jacket will only cost around £15, you’ll make your money back in the first year alone.

Pipe insulation is also straightforward to fit and the foam cylinder simply slips around any exposed pipes. Just as with the jacket, insulation will keep the water in your pipes warmer for longer.

Annual Saving DIY Cost Time Taken To Pay for Itself Carbon Dioxide Saving Per Year
Hot water tank top-up insulation (25-80mm) £20-£35 £15 Six months 90kg-120kg
Hot water tank jacket on an uninsulated tank £85-£130 £15 Less than six months 400kg-570kg
Pipe insulation £10 £20 Two years 45kg