Window Energy Ratings (WER's)

Since the changes to Part L of the Building Regulations in October 2010 there is a new method of complying to the building regulations. Part L of the building regulations (Conservation of fuel and power) is the area of the Building Regulations that covers thermal efficiency and energy efficiency. Previous to these changes, in order to get windows and doors to comply you needed to achieve a good overall U-value or specify a sealed unit with a centre pane U-value of 1.2 or less. The lower the U-value the less heat is lost through your windows.

Complying by simply specifying a sealed unit with a U-value of 1.2 has since been scrapped and replaced with the Window Energy Rating Scheme. The aim was for the WER to simplify, for consumers, the more complicated values for thermal efficiency, solar gain and air leakage into one basic A-G rating for overall energy efficiency.