How is an EPC Band Calculated?

An Energy Performance Certificate (EPC) is a simple way to understand the energy efficiency and carbon emissions of your home. It’s also a legal requirement if you’re building, selling, or renting a commercial or residential property.

The certificate demonstrates the performance of your building by using bands which range from ‘A’ to ‘G’, providing a useful summary of your property and also offering suggestions regarding the improvements you could make to improve your EPC rating.

So, how do these bands get calculated and what exactly do they mean? Let’s take a look.

What are the energy efficiency bands?

The energy efficiency bands help you to understand the performance of your home at a glance. There are seven of these bands on an EPC which are run on a sliding scale from ‘A’ (the most energy efficient) to ‘G’ (the least efficient). They are also colour coded for ease of reference from dark green (an ‘A’ rating) through to red (a ‘G’ rating). Most homes in the UK fall into a ‘D’ band.

In addition to energy efficiency, you’ll also be given an environmental impact rating which runs on the same scale, with the best rating being an ‘A’ (with a light blue colour) and the worst rating a ‘G’ (with a dark grey colour).   

How are the energy efficiency bands calculated?

To calculate your energy efficiency band, a qualified assessor will come to your property and look at a variety of factors to better understand how energy is used in your home. This includes looking at any potential for heat or energy loss, checking for insulation throughout the property, looking at how efficient the heating system and water is, inspecting whether you have double-glazing, energy efficient light bulbs, and so on.

Each segment of their inspection will be given a score depending on how efficient it is and what condition it’s in. The assessor will then calculate how energy efficient the property is and will provide an EPC rating for your property.

These are graded according to a points system which runs as follows:

  • EPC rating A = 92-100 SAP points
  • EPC rating B = 81-91 SAP points
  • EPC rating C = 69-80 SAP points
  • EPC rating D = 55-68 SAP points
  • EPC rating E = 39-54 SAP points
  • EPC rating F = 21-38 SAP points
  • EPC rating G = 1-20 SAP points

Once this has happened, you will then be given an Energy Performance Certificate which will detail both the energy efficiency and environmental impact of your property.

You’ll also find information such as estimated energy use, carbon dioxide emissions, fuel costs, a full summary of your property, and recommendations on what could be improved to increase your EPC band calculation.

What does this mean for your property?

If you had an EPC conducted on your property and didn’t get the results you expected, don’t panic. There are numerous ways that you can improve the energy efficiency of your home and therefore improve your rating, and many of them are relatively inexpensive.

For example, you could replace your light bulbs with LEDS, get a smart electricity meter, consider replacing your boiler, get double glazing, and consider using solar energy wherever possible.

It’s also important to note that the EPC is a requirement by law in the commercial and residential sector and is subject to increasingly strict guidelines.

For example, new rules called the Minimum Energy Efficiency Standards (MEES) came into effect in April 2018 which means that landlords with an EPC rating of ‘F’ or ‘G’ won’t be able to renew existing leases until they improve the property to a minimum of ‘E’.

This will also apply to all tenancies from 1st April 2020. This is set to tighten further by 2030 when the minimum EPC band is set to be a ‘B’.

Remember that the EPC isn’t there to punish you. It’s a great way to gain insight into the energy efficiency and environmental friendliness of your home and make a positive change for the future of our planet.


To recap, the EPC bands are calculated by conducting a non-invasive inspection of your property and giving each part a unique score.

Once the entire property has had its green energy survey, the EPC band will be calculated. This provides a rating and also provides useful information on what can be changed in your property to further improve your EPC band and help in the fight against climate change.