Building Regulations and Window Energy Ratings
UK Building Regulations
UK Building Regulations outline standards for thermal efficiency that must be met for all new and replacement windows. A minimum u-value of 1.6 Wm²K (whole window value), or a Window Energy Rating (WER) of A, B or C is required – although proposals for the future mean that this may change to a minimum u-value of 1.4 Wm²K or Window Energy Rating B or above.
A combination of different factors contributes to improved thermal efficiency in a window unit. Calculations for energy ratings, therefore, take these factors into account and consider the glass type, the components used in the sealed unit, the structure, and the window frame.
Building Regulations & WERs Page 1 of 3