ePrivacy and GPDR Cookie Consent by Cookie Consent Everything You Need to Know About Energy Efficiency

Everything You Need to Know About Energy Efficiency

11 min read
Aug '25 • by Marko Glibota

Quick summary

To make your home more energy efficient, focus on upgrading insulation, double glazing, and appliances with A-G labels, which can cost £30-£640 depending on the measure and home size. Grants may cover parts of these costs, and improvements usually pay for themselves within a few years through lower bills. Start by assessing your EPC grade or using an online calculator.

With energy prices at a record high and more potential rises possible in the months to come, now is a good time to start thinking about the energy efficiency of your home. As well as helping you to reduce energy bills, it could also help you lower your home’s carbon emissions.

This article aims to give you all everything you need to make your home more energy efficient from evaluating its current performance to tips to optimise energy use. We’ll also talk about the grants and financial resources available to make these changes.

What does energy efficiency mean?


Energy efficiency is not to be confused with energy savings. The principle of energy efficiency is to use less energy for the same quality of service, whereas energy savings are the gains obtained by reducing your energy consumption.

The purpose of energy efficiency is simply to reduce energy consumption while maintaining satisfactory conditions of use and comfort. It is therefore a question of consuming less - but, above all, better.

As an example, energy-efficient lighting has been revolutionised by light-emitting diodes (LEDs) and compact fluorescent lights (CFLs). These consume much less energy while providing the same level of illumination as conventional incandescent bulbs. A fluorescent lightbulb uses less energy while producing the same amount of light as an old-style light bulb. These are energy-efficient innovations.

To put it simply, something is energy efficient if it consumes less energy while performing equally as well as its conventional or traditional equivalent.

Energy-efficient improvements or measures can be undertaken in any aspect of life, but they are particularly relevant in the following sectors or industries:

  • Construction industry (residential or collective housing, urbanisation, equipment...),
  • Transportation (private vehicles, public transport, freight),
  • General industry (goods and services).

How is energy efficiency calculated?


In physics, the notion of energy efficiency is defined by the ratio between the level of useful energy that the system delivers and that of the energy consumed.

The energy efficiency of a device such as a refrigerator or heat pump can be calculated using the following formulas:

  • energy efficiency = useful output energy / total input energy
  • energy efficiency = useful power output / total power input

Although this mathematical clarification is interesting, what is the relevance for daily life? There are two simple ways of calculating the energy efficiency of your home. You can either use a home energy calculator or ask for a domestic EPC assessment.

1. Home energy calculators

Using an online energy calculator is one approach to determining the energy efficiency of your home, be it a house or an apartment. Although the results should be taken with a pinch of salt, a home energy checker is a helpful initial indicator of whether your home needs to be improved for better energy efficiency.

Just make sure the calculator you have chosen to use is independent. On their websites, many energy assessors offer free calculators that are intended to attract and drum up new business.
We advise you to try and find a website that isn't trying to sell you anything, such as the Energy Check on the website of the Energy Saving Trust.

An energy calculator provides a general overview rather than a thorough analysis. Some people are unaware of the insulation level in their walls or whether they have solid or cavity walls. This can cause individuals to input inaccurate data into the calculator and get unsuitable recommendations.

Don’t forget that an energy calculator offers extremely generic guidance that is not specific to the building and could therefore be incomplete.

2. EPC Ratings

Another way of calculating the energy efficiency of your home is to have a domestic EPC Assessment. This will give you a way more accurate result than a home energy calculator and will provide you with an “EPC” for your home.

An Energy Performance Certificate (EPC) is a mandatory real estate diagnosis giving an insight into the energy efficiency of a property. The rating you get is valid for ten years. To put it simply, the higher your EPC, the lower your energy emissions per square metre, and the more you save on your bills!

The EPC aims to assess the amount of energy and greenhouse gas consumed or released by a home.

If the property you own has been put up for sale or let, or modified in the last 10 years, then it will likely be legally required to have an EPC. The initiative to carry out an EPC belongs to the seller of the property or the lessor.

The energy diagnosis must be integrated into the real estate technical diagnosis file. It must be annexed:

  • to the promise to sell or to the deed of sale, if you are selling your property.
  • to the rental lease, if you are letting your property.

When the seller or lessor makes a real estate announcement for the sale or rental of their property, said announcement has to mention the energy performance scale of the home (A to G) and display the energy label (see image below).

EPC - energy efficiency rating

If you want to know more on EPCs, you can read through our dedicated article here.

Thanks to the 2018 MEES regulation, as a landlord you cannot sell or let a home with an EPC rating below E as of April 2020. MEES stands for Minimum Level of Energy Efficiency Standard.

This means that if your property has a F or G grade, you will have to undertake energy-efficiency renovation works. If you cannot improve your property to EPC grade E for £3,500 or less, you should make all the improvements that can be made up to that amount. You will then have to register an “all improvements made” exemption.

Can’t wait to find out what your EPC grade is? If you live in the UK, all you need to do is enter your postcode on this government website. If you live in Scotland, you’ll need this website.

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