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How efficient is your boiler?

Updated: Apr 16, 2023

A highly energy efficient boiler with a 94% efficiency rating would only waste 6% of the fuel it uses. By 'waste', we mean the gases that you see emitted outside through the flue pipe. To put boiler efficiency into financial terms, for every £1 you spend on heating your home with a boiler that's 94% efficient, 6p is wasted.

An inefficient boiler will burn through more fuel – costing you more on your heating bills – and will struggle to meet demand. Older boilers may be operating at efficiency levels as low as 60% to 70%!

The boiler efficiency percentage equates to ErP and SEDBUK energy labels.

What is ErP?

The Energy Related Products Directive (ErP) was launched as part of the EU's plans to phase out inefficient appliances, the Energy Related Products Directive (ErP) was introduced.

ErP applies to all residential and commercial heating products across Europe and has 2 key benefits:

* Clear energy labelling so consumers can choose the most energy efficient products. This makes it easier to reduce carbon emissions and save money on energy bills.

* ErP introduced new regulations for manufacturers known as 'Ecodesign'. Products, such as boilers, must now meet higher energy efficiency standards before they can be sold. Boilers that don't meet the required standard can no longer be manufactured or purchased.

Under ErP, boilers have to be labelled with their efficiency level from G (lowest efficiency) to A+++ (highest efficiency).

energy efficient boiler
energy efficient boiler

Boiler efficiency is the secret to lower heating bills.

The more efficient your boiler, the less fuel it will need. So if you upgrade an old inefficient boiler with a brand new model then you could be saving money each month.

There’s good news too because it’s never been easier to find a highly efficient boiler. That’s because modern boilers must be over 90% efficient, meaning that almost all of the fuel is turned into heat for your home or hot water.

You need to remember that over time, boiler efficiency will decline. That’s one of the reasons why it’s important to replace your boiler every 10 years or so. Fortunately, there are many things you can do to make your boiler more efficient and in this article we’ll share them with you.

Boiler manufacturers and retailers are responsible for ensuring their products are accurately labelled. Additionally, the installer who fits your new boiler must assess the energy efficiency of your entire heating system. For example, if they install an A-rated boiler with smart thermostat controls, the controls should improve the efficiency of your system and they will need to give you a rating for both combined.

What is SEDBUK?

When ErP ratings were introduced, they replaced SEDBUK. SEDBUK stands for Seasonal Efficiency of a Domestic Boiler in the UK and gives boilers an efficiency rating from A down to G. While it has been replaced, many boiler manufacturers still show the SEDBUK efficiency ratings of their boilers.

What is Boiler Plus?

On 6 April 2018, the Department for Business, Energy and Industrial Strategy (BEIS) introduced Boiler Plus. Boiler Plus has been designed to increase the efficiency of UK homes by ensuring that all new gas boiler installations meet certain requirements.

For a gas boiler to meet Boiler Plus requirements it must be at least 92% efficient (ErP), include time and temperature controls and feature one of weather compensation, load compensation, flue gas heat recovery or smart controls.

Why is boiler efficiency important?

Boiler efficiency is important for a number of reasons. By burning less fuel, an efficient heating system releases fewer carbon emissions into the atmosphere. This is great news for the environment as carbon is a leading cause of climate change.

If doing your bit for the planet wasn't enough, you'll also be doing your bank account some good too. As an energy efficient boiler burns less fuel, you could potentially be saving up to £580* per year on your heating bills.

How efficient is your boiler?

All boilers have an ErP efficiency rating which will tell you how efficiently the boiler will perform. You can see the efficiency ratings of all gas, oil and electric boilers available in the UK on our Boiler Efficiency Check.

If doing your bit for the planet wasn't enough, you'll also be doing your bank account some good too. As an efficient boiler burns less fuel, you could potentially be saving up to £580* per year on your heating bills.

How efficient is your boiler
How efficient is your boiler

As a boiler works to heat the home, it produces water vapour (steam). A non-condensing boiler releases this vapour out through the flue, along with any heat it contains. However, thanks to the Flue Gas Heat Recovery system within a condensing boiler, captures this heat and uses it to warm up the central heating.

If your gas boiler was installed after April 2005 then it will be condensing and, therefore, more efficient than a non-condensing boiler.

A condensing boiler is likely to be your greenest and cost savings option.

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