Benefits of Energy efficient windows explained

Published on: 12th June 2023


  • Reduce the amount of heat lost to the outside
  • Lower your energy bills
  • Keep your home warm in the winter

Making your doors, windows and conservatory more energy efficient will reduce your energy bills and lower your carbon footprint. Find out how to reduce the amount of heat lost and how to find a reputable installer.

Energy efficient glazing covers both double and triple glazing. These are windows with two or more glass panes in a sealed unit. You can also improve the energy efficiency of your home by installing secondary glazing, or even by using heavy curtains. Having energy efficient windows could help to reduce your carbon footprint and your energy bills.

Benefits of energy efficient windows include:

A more comfortable home.
Energy efficient glazing reduces heat loss through windows and means fewer draughts and cold spots.

Peace and quiet.
Not only do they keep the heat in, energy efficient windows insulate your home against external noise.

Reduced condensation
Energy efficient glazing reduces condensation build up on the inside of windows.

Installing energy efficient glazing

Before replacing your windows, check with your local planning office if any of the following apply to your property:

  • You live in a conservation area.
  • You have an article 4 direction on your property, removing the right of permitted development.
  • You live in a listed building.

Most people have double or triple glazing fitted by a professional. Competent DIYers can fit some secondary glazing systems, but a professional should carry out removing old windows and installing new ones.

Energy efficient window materials

Energy efficient windows come in a range of frame materials and styles. The energy performance of a window depends on how well these materials stop heat from passing through, as well as how much sunlight travels through the glass and how little air can leak around the window.

Energy efficient windows are made of two or three glass panes sealed in a single unit, surrounded by a frame made from uPVC, wood, or another material.

  •  Double-glazed windows have two sheets of glass with a gap in between, usually about 16mm.
  •  Triple-glazed windows have three sheets of glass, and two gaps. This can make them better at insulating than many double-glazed windows, but it’s not always the case.

The gaps between the glass panes are filled with air, or an inert gas such as argon. The air or gas is completely sealed.

Choosing an efficient window

The energy performance of a window is influenced by a wide range of factors, so it’s not easy to choose a window by looking at how it’s made. Fortunately, there’s a rating scheme to help you find the most efficient.

Window manufacturers can show the energy efficiency of their products using an energy-rating scale from A++ to E. The entire window (the frame and the glass) is assessed to allow for heat loss, draughts and solar gain, giving a rating that indicates the overall impact of fitting that window in your home.

The British Fenestration Rating Council (BFRC) runs the scheme. To choose the most energy efficient window, look for the BFRC rating.


Windows that have an energy rating will have the ‘u-value’ of the window displayed on the energy label, and you may see u-values quoted for windows without a label.

A u-value is a measure of how easily heat passes through a material, but it is not a complete measure of how efficient a window is. The overall label rating will give you a better indication of the window’s energy saving potential.

This article is credited to ‘energy saving trust’.