Determination of Proper Insulation Thickness for Building Walls Regarding Economic Consideration

Determining the thickness of the thermal insulation to be applied to building walls is economically important as well as energy saving. In this study, the thermal insulation thicknesses for building walls were determined based on the cooling and heating energy requirements. Life cycle cost analysis considering a certain lifetime period was used to determine the proper insulation thickness. The most suitable insulation thickness calculations in terms of economy were performed for a sample city which has heating and cooling loads. The sol-air temperatures were calculated taking into account the solar radiation falling on vertical surfaces (such as external walls), and then they were used to determine the degree-day (DD) values. As a result, the variation of insulation thicknesses with the heating, cooling and annual energy requirements of buildings based on the seasonal or annual energy requirements were presented comparatively. The economic insulation thickness was found to be 4.7 cm.