Combination Boiler or ‘Combi’ Boiler
As you can probably guess, a combination boiler provides both heating and hot water on demand, making it a very energy efficient boiler as it’s a single unit (hence the name combination). As a new combi boiler will heat the hot water instantly when you turn the hot water tap on, you won’t need a hot-water or cold-water storage tank, which can be a real space saver as well as a more efficient way of heating your home. It also means there’s less chance of any pipes freezing in the loft if you’ve got a cold water storage tank.
The added benefit of a new combination boiler is that the hot water is delivered at mains pressure, so you should get a nice powerful shower without the need for a separate pump/pressure shower if you have god mains water pressure.
The downside of a new combination boiler is they are really only suitable for smaller properties. Larger houses and properties with more than one bathroom, a system boiler will be required.
Whilst a System Boiler requires a hot water storage cylinder, all the major heating and hot water components are situated within the boiler itself, meaning they are quicker and easier to install.
A system boiler will provide a constant supply of hot water, meaning you don’t have a slight delay in hot water coming through like you do with a Combination boiler as the System boiler has already heated the water. Although a system boiler does need a hot water storage cylinder, it doesn’t have to be positioned in the loft and can be easily installed in an airing cupboard, making it an ideal cupboard to dry clothes.
These boilers are also compatible with solar water heating systems, which can save you money on your heating bills by heating your water with the power of the sun.
Heat Only Boilers – also known as Regular, Conventional or Open Vent Boilers
Heat only boilers do exactly what they say; They heat your central heating and hot water when installed as part of a heating system together with a hot water storage cylinder, cold water storage tank, plus a feed and expansion tank (which is usually stored in the loft above the boiler to provide a good head of water).
If your boiler is very old, the existing radiators and pipework might not cope with the pressure a new combination or system boiler would generate. Therefore, you are much better off replacing the boiler like for like with a Heat Only Boiler, unless you are having the whole system replaced, including pipework and radiators.
A Back Boiler is a boiler supplying hot water or heating that is built-in behind a fireplace or is an integral part of a gas fire. They are often fitted to a property when space is at a premium as the boiler is fitted into the existing fireplace, rather than taking valuable floor or wall space elsewhere in the home.
Since the Building Regulations change in 2005 came into effect for energy efficient condensing boilers, your choice of replacement Back Boiler is limited by what’s on offer from the manufacturers. At Go Plumber, we usually recommend that you replace a Back boiler with a modern, energy efficient combi boiler.