This is the Prelaq Energy web calculator. It is based on a simple “infinite flat roof”- model of a building and calculates the exterior and interior surface temperatures of the roof and the momentary heat flux through the roof under given input conditions. This is done by solving the heat transfer equations, including solar absorbtion, thermal emittance and wind convection on the exterior surface, radiative and convective heat transfer on the interior surface and conduction heat transfer between the two surfaces.
Note that the results are valid only under the given input conditions and may vary strongly during the year depending on climate.
To the Prelaq web calculator
Assumptions and simplifications