The U value of a bifold doors measures how well it insulates buildings. A lower U value means that it is more efficient in reducing heat loss and improving insulation. Current building regulations require that a "bifold" door set have a U value less than 1.4wm2k for replacement, new builds, and extensions. As this is the key figure in the regulations, it is crucial to obtain the U value for the entire bifold set. Some companies only give the glass' value. This is often lower than the entire set value. Doors of the same thickness as uPVC or thermal-break aluminium have better thermal performance than wooden doors. Thermal breaks are a low-temperature conductive material, such as polyamide, that is placed between aluminium and prevents energy from flowing between them. Aluminium is a very good thermal conductor, so it is important to have a thermal break when making windows and doors. Our range of bifold doors for external use have U values that are based on the complete bifold set. They easily surpass the regulations.