What is ErP? Boiler Efficiency Explained

ErP stands for the Energy related Products Directive.

boiler flat

It is an energy efficiency rating system introduced by the European Union (EU) in September 2015. ErP replaced the UK’s SEDBUK (Seasonal Efficiency of Domestic Boilers UK) rating system. But what exactly does it mean and how could it help you lower your energy bills? Here’s what you need to know about ErP…

What Does Boiler Efficiency Mean?

A boiler’s energy efficiency is determined by how much of the fuel it uses is converted into usable energy vs. how much fuel is wasted in the process. It is calculated as a percentage which equates to a letter rating. For example, if a boiler is 90% efficient, 10% of the fuel used by the boiler is wasted. In financial terms, for every £1 you spend on heating your home, 10p is wasted.

Get FREE Boiler Quotes

Get quotes from local engineers for a new energy efficient boiler now


Why is Boiler Energy Efficiency Important?

For most people 50-60% of our energy bills come from heating our home. The more energy efficient your boiler is the cheaper your energy bills will be. In addition, when a boiler wastes fuel it emits this as carbon into our atmosphere. There will not be a particularly noticeable reduction in your bills if you’re swapping an 88% efficient boiler with a 91% model, but there are big savings to be made by swapping older G rated boilers with modern heating systems.

The Energy Saving Trust estimate the following annual savings are possible when replacing a G rated boiler with an energy efficient model. When you consider that the average lifespan of a boiler is around 10-15 years, the potential savings are significant.

House Type Annual saving when replacing G rated system (Efficiency <70%) Annual saving when replacing F rated system (Efficiency 70-74%) Annual saving when replacing E rated system (Efficiency 74-78%) Annual saving when replacing D rated system (Efficiency 78-82%)
Semi-Detached £200 £140 £120 £120
Detached £305 £210 £180 £180
Detached Bungalow £155 £105 £90 £90
Mid terrace house £175 £120 £105 £105
Mid floor flat £95 £65 £55 £55

Why Did ErP Replace SEDBUK?

It’s all about reducing our negative impact on the environment by lowering Europe’s carbon emissions by 20% by 2020 (compared to 1990 levels). The EU intends to phase out appliances which are inefficient, reduce our reliance on fossil fuels like oil and gas and increase our use of renewable energy by 20%.

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

  • Energy labelling is now clearer so consumers can choose the most energy efficient products, enabling them to both reduce their carbon emissions and save money on energy bills.
  • ErP introduced new regulations for manufacturers known as ‘Ecodesign’; products like boilers now had to meet higher energy efficiency criteria before they could be sold. Boilers which didn’t meet the required standard could no longer be manufactured or purchased, and only those which had been purchased before 15th September 2015 could be installed.
  • Then Came Boiler Plus…

    ErP was rolled out in September 2015, but since then the UK government has gone one step further in the quest for better energy efficiency.

    In April 2018 the Boiler Plus legislation came into effect raising the minimum efficiency level of all gas boilers manufactured and installed in England to 92% ErP. It also stated that other energy efficiency measures must be taken such as:

  • Time and temperature controls are required for all gas and oil boiler installations
  • Combi boiler installations must also include one of the following: Weather compensation, Load compensation, Flue Gas Heat Recovery, Smart controls.
  • While ErP labelling was the responsibility of manufacturers, retailers and installers, Boiler Plus also requires consumers to step up; homeowners who knowingly allow a non-compliant boiler installation to be carried out could face prosecution and fines of up to £5,000.

    Get FREE Boiler Quotes

    Get quotes from local engineers for a Boiler Plus compliant boiler now


    What’s the Difference Between SEDBUK and ErP?

    Originally SEDBUK ratings were represented by letters A – G. However, since ErP was introduced which also uses letters (A+++ to G), the SEDBUK letters have been withdrawn to avoid confusion. SEDBUK energy efficiency is now usually displayed as a percentage.

    The newer ErP ratings are calculated slightly differently to the older SEDBUK ratings; the result is that boiler efficiencies appear lower under the ErP system. In addition, modern condensing boilers are now required by law to meet a minimum efficiency of 92% so most new boilers will meet this standard. This means there is no real point of difference for consumers to compare and is why many manufacturers choose to show both the SEDBUK percentage and the ErP rating. If you are interested in comparing the energy efficiency of boilers then the SEDBUK figure is the best way to do this, but there is rarely more than 1-2% between new boilers.

    Note: When comparing SEDBUK figures you may see both SEDBUK 2005 and SEDBUK 2009 as the SEDBUK rating system was adjusted in 2009 to use percentages rather than letters. Some older boilers were tested for efficiency against the SEDBUK 2005 criteria. For an idea of the difference between, a Sedbuk 2005 90% efficient A-rated gas, oil or LPG boiler works out as 88% efficient under the Sedbuk 2009 system. Check the energy efficiency of your boiler at Home Heating Guide.

    ErP Energy Labelling

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

    The ErP label looks like this:

    Picture of a 2015 boiler erp label

    Source HHIC

    Manufacturers and retailers are responsible for ensuring their products are accurately labelled and the installer who fits your new boiler is responsible for assessing 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.

    Get FREE Boiler Quotes

    Get quotes from local engineers for a new energy efficient boiler now