Boilers: efficiency, types, and what to choose
Heating and hot water can make up over half of yearly energy spending—so the right boiler can make a real difference.
Why condensing boilers matter
Modern boilers generally burn fuel efficiently when serviced and maintained. Still, some heat escapes through the flue
(the pipe that removes fumes and brings in fresh air).
Condensing boilers are more efficient than older models because they capture and reuse heat from gases that would usually be lost up the flue.
How to tell if yours is condensing
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Plastic flue: If the flue is plastic, it’s likely condensing. If it’s metal, it usually isn’t.
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Plastic drain pipe: A plastic pipe from the boiler to a drain is a common sign.
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Install date: Gas/LPG installed after 2005 or oil after 2007 is likely condensing.
Boiler types at a glance
Combi boilers
Combi boilers don’t use a hot water cylinder—heat and hot water come directly from the boiler.
They’re a good option when space is limited and are often the least expensive type.
System boilers
System boilers use a separate cylinder to store hot water. This makes them great for homes with higher demand,
though some heat is lost from the cylinder over time.
Heat-only boilers
Heat-only (regular/conventional) boilers are similar to system boilers but typically require two extra header tanks
for cold water storage, often placed in a loft.