Gesamtwärmedurchgangskoeffizienten

Gesamtwärmedurchgangskoeffizient, often abbreviated as U-value, is a measure of heat transfer through a building element, such as a wall, roof, or window. It quantifies how much heat passes through a square meter of a material or composite structure when there is a temperature difference of one Kelvin across it. The unit of measurement for the U-value is Watts per square meter Kelvin (W/m²K). A lower U-value indicates better thermal insulation, meaning less heat is lost from the building in winter and less heat enters in summer.

The calculation of the Gesamtwärmedurchgangskoeffizient involves considering the thermal resistance of each layer within the building element. Thermal resistance is the inverse of thermal conductivity, which describes how well a material conducts heat. For a composite structure, the total thermal resistance is the sum of the thermal resistances of all its individual layers, including any air gaps and surface resistances. The U-value is then the reciprocal of this total thermal resistance. Building regulations and standards often specify maximum U-values for different building elements to ensure energy efficiency and occupant comfort. Reducing U-values through the use of insulation materials and improved construction techniques is a key strategy in sustainable building design and reducing energy consumption for heating and cooling.