The starting point of every heat load calculation: building constructions and their thermal transmittance (U-value).
Constructions such as walls, floors, ceilings and roofs are composed layer by layer from a material database. Each material is defined by its thermal conductivity coefficient λ (W/mK): a material with a high λ is a good heat conductor, and one with a low λ is a good thermal insulator.
The calculated U-values are used directly in the heat losses and heat gains modules, so each construction is defined only once for the whole project.
