What is the U-value for external roofs?

The U-value is a measure of thermal transmittance, indicating how effective a building element is as an insulator. It quantifies the rate at which heat is transferred through a structure, such as roofs, walls, or windows, and is expressed in watts per square meter per degree Kelvin (W/m²·K). A lower U-value represents better insulating properties.

In the context of external roofs, the U-value can vary depending on building codes and energy efficiency regulations in specific regions. For many building standards, including those influenced by practices like Estidama, a U-value of 0.31 W/m²·K is considered a significant benchmark for external roofs. This value demonstrates an appropriate balance between energy efficiency and existing material technologies while ensuring comfortable indoor temperatures and reducing energy consumption.

The selection of 0.31 W/m²·K reflects an understanding of contemporary building practices aimed at achieving sustainability and energy efficiency standards.