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Your guide to window energy ratings

There are numerous benefits that go hand-in-hand with the installation of energy efficient windows and doors. Designed to keep cold air out and warm air in, the latest energy-efficient window units help property owners realise a vast range of advantages, including better comfort, increased light, and less condensation. Replacement windows are also great to look at, but one of the main reasons why people choose to upgrade is to make energy savings.

Energy efficient windows aren’t just responsible for you saving money on your annual energy bills, they also help to save the planet. According to this Department of Energy & Climate Change (DECC) fact sheet, around 18% of heat loss occurs through a property’s windows. With around twice as much heat lost through single glazing than standard double glazing, an upgrade will ensure more energy is saved when heating your home, particularly during the winter months. Investing in high quality window replacement is a must, which makes understanding the energy ratings used to classify windows in the UK important.

How are windows rated in the UK?

Whilst the US government uses ENERGY STAR and NFRC labels to communicate the quality of windows and ensure homeowners have the information they need to select the best quality for them, UK windows are rated from A++ to E. This sliding scale – A++ representing the best quality and most efficient – is used by the majority of window manufacturers. Unlike many systems used elsewhere in the world, our window energy ratings rate the energy efficiency of the entire window – not just the glass.

What do these ratings mean?

Overseen by the British Fenestration Rating Council (BFRC), each rating represents a U-value and is generally displayed on the energy label of the product. As well as windows and doors, you’ll find these energy labels on other products, including appliances like fridges, freezers and washing machines. The energy ratings and the associated level of efficiency are generally displayed as one of a selection of coloured bars, with the rating achieved by the window or door clearly identified.

Are U-values and ratings the same?

Although U-values and window energy ratings work together to provide a clear picture of efficiency for buyers, the U-value can be used to reveal its own findings as Energy Saving Trust details:

“A u-value is a measure of how easily heat can pass through a material. Materials that let out more heat have higher u-values whereas materials that let less heat pass through them have lower u-values. In some cases, windows with a higher energy performance rating might have a higher u-value than windows with a better energy efficiency rating. This might seem the wrong way round as lower u-values indicate better insulation levels. However, in these cases it will be that there are other aspects of the window that make them better overall such as coating used on the glass and the gap between the glass panes.”

Why stop at energy efficient windows? Complete your home upgrade project with our range of energy efficient doors. Find out more about the benefits of energy efficient door installation, or contact our team direct to get started.