U-values are not used in Tas calculations and are displayed for information purposes only.
For transparent constructions, the U-value calculation is based on EN673.
For opaque constructions, the U-value is based on ISO 6946, and there are two columns. The external column displays the U-values for the construction when it is used on a building element that has one side exposed to the outside. The internal column displays the U-value for the construction when it is used on a building element that has neither surface exposed to the outside. Both columns display the U-value for each type of flow direction, horizontal, upward, and downward.