Choosing a boiler FAQs

When choosing a new boiler, you've probably got a few questions - it's not always obvious how to choose a boiler. So to help, we've created a boiler FAQ section below.

Frequently asked questions when choosing a new boiler:

What is SEDBUK?

The higher the SEDBUK rating your boiler has the less carbon dioxide you will be emitting into the atmosphere when you are warming your house, washing your pots or having a bath. In money terms, by installing a SEDBUK A rated boiler, for every £1 you spend on gas to power your boiler, between 90p and 94p is turned into useful heat and hot water. With a SEDBUK B boiler this reduces to between 86p and 89p out of every £1 and for standard efficiency boilers this is even less.

Boilers for heating and hot water use much more energy than any other household appliance. For an average household with central heating, 84% of its energy consumption is for heating and hot water. So if you don't know how to choose a boiler, it's important to choose an efficient one, and have it installed in a correctly designed system - both for money-saving and for the environment.

The Energy Savings Trust, set up by the Government to promote energy efficiency, also advises that the largest saving in home energy costs is from a more efficient boiler, even ahead of wall insulation.

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What makes a boiler efficient?

When choosing a new boiler efficiency is important. An efficient boiler is one that turns as much of its fuel into useful energy with as little as possible wasted.

A condensing boiler is always more efficient than a non-condensing boiler.

A condensing boiler works by extracting as much heat as possible from the flue gases this is done by a large heat exchanger. In the process of doing this the temperature of the flue gases is reduced from 150-200 degrees centigrade down to 50-60 degrees centigrade, creating a water vapour called condensate. This is not harmful it is just a sign that your boiler is working efficiently. Your installer will fit a drain to remove the condensate from your system.

Overall system efficiency is dictated by many different factors, which including the type of boiler, radiator size, system controls (pumps, programmers, thermostats), regular servicing, and so on.

High Efficiency boilers are designed to fit as easily onto an existing system as a standard efficiency boiler, with no changes to radiators.

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What is pluming?

A classic boiler FAQ. Pluming is the name for the vapour that you will see coming out of the flue as a result of the boiler condensing the flue gases. All boilers do this, but it is more noticeable with High Efficiency boilers. Plume is not harmful but can be viewed as unsightly and can potentially be a nuisance if it drifts across neighbours properties or public areas. This can be easily remedied by fitting a Glow-worm Plume Management Kit to the end of the flue, which redirects the pluming and makes it less noticeable. You should consider this when choosing a new boiler.

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What are the benefits of a High Efficiency A-rated boiler?

You will save money. In effect you will get a permanent discount on gas bills of up to 35%.

The reduction in gas bills starts from the moment you fit a High Efficiency boiler. If you set that against the extra cost of buying the boiler, the savings will outweigh the cost within 2 to 3 years. This depends on various factors including house size. But after that the boiler will last for many years and the savings will increase in line with fuel costs - a huge factor when choosing a new boiler.

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What is the lifespan of a High Efficiency A-rated boiler?

When deciding how to choose a boiler, you can reasonably expect a high efficiency boiler to last anything from 10 to 15 years, although this depends on how much is it used and is no less than a modern standard efficiency boiler.

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Why should I fit controls to my heating system?

When choosing a new boiler you should also consider how it is controlled. Adding controls to your system, whether inbuilt or external, will make your system more efficient and will provide you with more consistent levels of home comfort. To comply with Part L of the Building Regulations you must at least have a simple room thermostat as part of your heating system.

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How do I check that an installer is Gas Safe registered?

See our section on choosing an installer

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