HOW TO CHOOSE AN OPTIMAL THERMAL INSULATION THICNESS FOR THE BUILDING ENVELOPE

The thermal insulation of new buildings or existing one consists in applying a layer of thermal insulating material, usually on the outer surface of the building envelope. Generally in the case of a new building construction or in the case of an old / existing building thermal retrofitting, the thickness of the thermal insulation is recommended (based mainly on the designer experience of practice in this field) and then it is verified if the correct thermal requirements are satisfied. From economic reasons, it is important to know the minimal thickness of the thermal insulation layer that can cover all the requirements of a good thermal insulation. Currently the only way to find this 'minimal thickness' is by the consecutive try-out method, namely to make reiterative calculations mainly for the corrected specific thermal resistance (R') and the overall factor of thermal resistance (G), buts this supposes a laborious work. Anyway, if for these calculations it is applied a suitable methodology, than the supplementary work is reduced considerably. It was considered useful to find a way to be able to determine the optimum thickness of insulation layer, in the sense of adequate minimum thickness, without using an laborious iterative computation, which is difficult to be accepted from the practical point of view.