Environmental Optimization of Building Insulation Thickness in Warm-Dry Regions

In this study, the environmental effect (CO) of rock wool as a mineral insulation material and expanded polystyrene as a polymer insulation material for a residential building is studied. Initially, the intended building is simulated in Design Builder for warm-dry climate regions like Yazd and Isfahan cities and then the effect of different thicknesses of these two insulation materials inside the external wall of the building is studied towards optimizing the thickness value environmentally. Despite the CO emissions generated by cooling and heating systems while consuming energy throughout the year, embodied CO values in the manufacturing process until installation are also considered. Eventually, using the Energy Plus simulation engine inside Design Builder and MATLAB software, the environmental optimum insulation thickness regarding emission and embodied values of CO for a lifetime of ten years in warm-dry regions of Iran such as Yazd and Isfahan cities are calculated. These values for expanded polystyrene are found to be 20 cm for Isfahan and 19 cm for Yazd and values for rock wool are 11 cm for Isfahan and 10 cm for Yazd. Thus, a mineral insulation material such as rock wool has a smaller environmental optimum insulation thickness than a polymer insulation material such as expanded polystyrene.