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What is SEDBUK (Seasonal Efficiency of Domestic Boilers in the UK) Rating?

You may not realise it, but your boiler accounts for 55-60% of your annual spend on energy. If your boiler is operating inefficiently, there’s a very good chance you could be wasting both fuel and money. By replacing their boiler the average family could reduce their annual bill by as much as £300.

But how do you know which boilers are the most energy efficient? You need to take a look at something called the SEDBUK rating which you can view in our boiler efficiency tables.

What is SEDBUK?

SEDBUK stands for ‘Seasonal Efficiency of Domestic Boilers in the UK’.

It is an energy efficiency rating scheme which was developed by boiler manufacturers and the UK government to enable a fairer comparison of the energy efficiency of boilers. Now every boiler has been awarded a rating from A to G based on their average annual energy efficiency.

An energy efficient boiler will produce less emissions and use less fuel which in turn should lower your energy bills.

How is energy efficiency calculated?

The theory behind SEDBUK calculations is based on 3 years of laboratory research and tests which examined 20 different boilers. The results of these tests were combined with other factors such as type of boiler, fuel, ignition method, climate, water content and typical domestic usage patterns. In addition, trials were carried out in 99 homes to support the laboratory theory.

Using the SEDBUK test, boilers are graded A – G. A is the best grade a boiler can receive and means it has an efficiency level of 92% or above. This means they turn 92% of the fuel they use into energy, with only 8% wasted. These boilers are usually condensing boilers. An older, G rated boiler could be wasting as much as 30% of the fuel it uses which equates to around 30p for every £1 you spend on fuel. Generally speaking, all boilers should be condensing and rated either A or B for energy efficiency.

As of 2010, all new boilers installed in domestic properties need to be at least B rated.

What is a Condensing boiler?

Condensing refers to the condensation which is created within the boiler as a byproduct of heating water.

In a traditional boiler, this is turned to water vapour so it can be expelled as a waste gas. However, a condensing boiler will turn this vapour to energy to be recycled back into the system. As less energy is lost in waste gases, the boiler doesn’t need to use as much fuel. This makes them both more energy efficient and cheaper to run.

How efficient is your boiler?

There are several ways to find out how energy efficient your boiler is. Your boiler manual should state this in the specification, however you need to remember that the efficiency of a boiler declines as it ages so the stated figure may no longer be accurate. If you recently bought your home it’s likely that this information will have been included with your sales documentation.

Or, even easier, just take a look at our boiler efficiency tables to check the efficiency of your boiler and see if you could be saving money with an A rated boiler.


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