Boiler Efficiency Ratings

Compare boiler efficiency ratings to find out if a replacement boiler could save you money on your energy bills.

Find out the energy efficiency rating of your boiler by selecting the make and model below.

Boiler Efficiency Explained

A boiler’s energy efficiency rating is an indicator of how much it’s going to cost you to run. It’s a great way to compare new boilers to find out which model is likely to save you more on your energy bills. If you are currently using an old boiler, it’s likely that you could save money by replacing it with a modern energy efficient boiler.

What are SEDBUK Efficiency Ratings?

From 1999 to 2015 boilers were ranked on the SEDBUK scale which stands for ‘Seasonal Efficiency of a Domestic Boiler in the UK’. Although SEDBUK 2009 and 2012 was replaced in 2015 by the Energy related Products Directive, or ErP, many manufacturers still refer to SEDBUK as it gives a more detailed efficiency rating.

What Is The ErP Directive?

The ErP Directive came about because of the EU’s ambition to improve the energy efficiency of our homes and achieve the following targets by 2020:

  • 20% reduction in EU greenhouse gas emissions (compared to 1990 levels)
  • 20% improvement in overall energy efficiency (across the EU)
  • 20% more energy produced from renewable resources such as solar or biomass.

Under the current ErP standards, boiler manufacturers are required to label their products with a rating from A+++ to G, with G being the least efficient.

How to Choose the Most Energy Efficient Boiler?

The issue with ErP, however, is that nearly all modern condensing boilers have an ErP rating of A which gives homeowners nothing to compare when looking for the most efficient model. The SEDBUK rating system assigns a percentage (usually between 70 – 92%) which represents how much energy is used vs. wasted when heating your home. For this reason, many homeowners tend to compare the SEDBUK efficiency rating of potential new boilers rather than the more recent ErP energy label. You can get modern, A-rated condensing in all types of boilers including combi boilers, system boilers or conventional boilers to suit your home’s central heating system.

How Much Money Could I Save with a More Efficient Boiler

To understand how a new boiler could save you money, you need to consider the energy that an inefficient boiler is wasting. For example, if a boiler is only 70% efficient, for every £1 you spend on heating your home, 30p is being wasted on lost energy. If your new boiler can reach efficiency of 90%, that is just 10p lost of every £1. So that’s a saving of 20p in every £1 which really adds up over time.

While ErP came into force in September 2015, in April 2018 the government’s Boiler Plus legislation raised the minimum efficiency level of all gas boilers manufactured and installed in England to 92% (ErP). The regulation also stated extra heating controls need to be incorporated to give the homeowner maximum control over their energy use:

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.

The financial savings you could make by replacing your boiler with a more efficient model can be significant, but will vary depending on the size of your home, the fuel used by the boiler and the inefficiency of your existing boiler.

On average, households which replace their old gas boiler (with a standard programmer and room thermostat), with a new A-rated condensing boiler with a programmer, room thermostat and thermostatic radiator controls (TRVs) could save up to*:

ErP Rating of Old Boiler Efficiency Detached house Semi-detached house Mid-terrace house
D 78 – 82% £165 £135 £115
E 74 – 78% £205 £150 £130
F 70-74% £255 £170 £145
G <70% £365 £240 £205

*Figures taken from the latest research by the Energy Saving Trust. Based on fuel prices as of November 2021.

For new boiler installations visit Boiler Guide to request quotes from independent local and regional heating engineers.

Boiler Efficiency and The Environment

It’s not all about money when it comes to boiler efficiency. If a boiler is inefficient, i.e. using more fuel than necessary to heat your home, it is also contributing more carbon emissions into the air. Natural gas and oil are fossil fuels which produce carbon dioxide when burnt.

Carbon is a greenhouse gas and the high levels of it in our atmosphere are heating up the planet. This increasing temperature is causing our climate to change which will lead to more and more unpredictable and extreme weather such as melting ice, rising sea levels and eventual flooding. If significant action is not taken to tackle climate change, both animals and humans will find it more and more difficult to inhabit the planet.

The fossil fuels we burn both in industry and to heat our homes are a major contributing factor to climate change, so it’s vitally important that we make minimise our carbon footprint as much as possible. Using a boiler which is as energy efficient as possible is essential, but the ultimate objective is for the UK to find alternative renewable heating solutions which don’t emit carbon into the atmosphere.

Renewable Heating Alternatives

While our stores of fossil fuels will run out and add carbon to the atmosphere, renewable energy is sourced from nature, will replenish on a human timescale and is either carbon free or carbon neutral. Renewable heating systems often have low running costs as they run on free resources and you’ll be buying less energy from a supplier, which means reduced heating bills in many cases.

Heat pumps take latent heat from the air, ground (or water from lakes and rivers) and use it to heat water or air for use in the home. Solar thermal panels absorb energy from sunlight to produce hot water. Biomass boilers are like gas and oil boilers except they burn wood pellets or similar to produce energy. This is carbon neutral, i.e. the pellets don’t emit any more carbon than was in the tree to begin with.

Take a look at our articles on renewable energy for more information on the benefits of renewable heating systems.