What maximum U-value is mentioned for fenestration?

The maximum U-value for fenestration is a critical measurement regarding a building's thermal performance. It indicates the rate at which heat is transferred through a unit area of the fenestration (such as windows and doors). A lower U-value signifies better thermal insulation, meaning less heat transfer and better energy efficiency.

The value of 2.2 W/m².K aligns with the standards outlined for ensuring adequate energy efficiency in buildings, primarily within the context of sustainable design principles. This benchmark helps ensure that fenestration not only contributes to the aesthetic and functional aspects of a building but also meets energy conservation criteria, which is crucial in sustainable practices like Estidama.

Other values mentioned may either be too high or not meet the required efficiency standards set forth by energy guidelines, emphasizing why the 2.2 W/m².K figure is preferable for fenestration in achieving optimal energy performance in buildings.