U-Values Explained

The U-Value on a door or window measures how quickly the heat from the inside leaks to the outside. The lower the U-Value the better insulated the door or window is.

When calculating U-Values the glass and frame have to be considered. We offer a wide range of specifications with our lowest U-Value at 1.2W/m²k for our flush casement windows, and as low as 1.1W/m²k for our sash window range.