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Help & advice
It's easy to be confused by the different types of boiler and heating system available. Our simple guide is designed to help you make the right choice for your home.
Fuel types
The most popular fuel systems used in the UK are natural gas, oil and LPG (liquefied petroleum gas). Other types include solid fuel (coal and wood burning) and green energy products such as solar and ground source heat pumps.
The system you choose will normally depend first on the location of your property. Where natural gas is available, it is normally the first choice due to its cost and convenience. In rural areas with no natural gas supply the choice is more complicated: in simple terms, LPG is more convenient but tends to be more expensive than oil.
Types of system
The key difference is in the way they provide hot water in your home. All provide heating to your radiators in a similar way.
01
Hot water is heated indirectly by the boiler and stored in a cylinder. It is pressurised by water from a header tank, usually in the loft, along with a smaller header tank for the heating circuit. Tap pressure depends on how far below the header tank the taps are, which may mean too little pressure for an upstairs shower.
02
Combis heat water instantly, so you don't need a hot water cylinder or a storage tank in the loft. That makes them good for smaller properties, including flats. But flow rates depend on the boiler's capacity and drop when a second outlet is opened, so combis aren't ideal for busy homes with several bathrooms.
03
All the major components, including the pump and expansion vessel, are built into the boiler, so there is no separate feed and expansion tank in the loft. Paired with an unvented cylinder fed by the mains, there is no loft storage tank and your hot water arrives at near mains pressure.
Each of the three systems can use a condensing (or non-condensing) boiler. "Condensing" means the boiler recovers heat from its flue gases that would otherwise be lost, condensing water droplets inside the boiler. The efficiency advantage is significant: typically 88 to 95% for condensing boilers, compared with 75% for non-condensing boilers.
It depends on your property and your circumstances. A combi may be ideal for a single person in a flat; a large family may benefit from a system boiler with an unvented cylinder. We take time to discuss your circumstances and requirements so we can recommend the most appropriate system.
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