In 1991, when I started Living Shade with Svensson in Sweden, we had screens called ULS. This type of screen was developed in the early 80’s to reduce heating costs resulting from the 1982 oil crisis. Growers realised the screen also worked well in the middle of summer for reducing plant temperature and by the 1990’s there were about 30 to choose from. More and more growers realised the importance of controlling light, heat and relative humidity with the resulting higher output and quality with lower costs.By the year 2000 there was a complete change – ULS screens knitted together with black thread. Dutch growers did not like this as it created heat inside the glasshouse in summer and so Svennson changed to clear thread screens (XLS). By using clear thread instead of black thread there was up to 7% more light, with less heat produced inside.