In order to design cooling and heating systems of each building, it is necessary to calculate heating-cooling load of desired location in the first step. One of the important parameters in determining the heating-cooling load of buildings is the thermal resistance of the wall s/roofs of the building. To determine walls/roofs thermal resistance, so far, many tables and references published that National Building Regulations have provided complete collection to the engineers in its entirety in the nineteenth section. In this regard, in order to ease the calculation of thermal resistance, the BTS Industries Group has designed the present application and provided it to its audience. This program, taking into account various constructional materials and thicknesses, achieves total thermal resistance in any wall or roofs.