What should you look for in an energy efficient bi-folding door?
U-values, measure how effective a material is as an insulator. The lower the U-value, the more efficient the material. The more efficient the material, the lower your energy bill will be. With bi-folding doors you generally want a value of 1.4 or lower to ensure that you have optimal thermal performance. There is a variety of energy-efficient bi-folding doors, with low U-values. For example, WarmCore doors have been developed to achieve a U-value of 1.4W/m2K with double glazing, and a U-value of 1.0W/m2K with triple glazing.