Optimum Thickness of Outside Sheathing Insulation for Exterior Walls of Building Envelopes

Due to the high heat losses in the buildings, using thermal insulation for external walls is a very effective method to decrease the building energy demand and their influences on environment. The goal of this work is to determine optimal exterior sheathing thickness to make energy consumption in the buildings more efficient. The P1-P2 method combined with the degree day method is used to predict the optimum sheathing thickness for the United States test cities. The rockwool and insulating board are considered for the insulation materials. The sheathing thickness must be chosen near the optimum point to augment energy savings in the buildings. It is seen that the rockwool material having low thermal conductivity leads to a reduction in the payback period and insulation thickness with high net savings. The optimal insulation thicknesses of 0.064 m and 0.12 m with the payback period of 4.4 and 5.9 years were determined for the rockwool and insulating board, respectively, in New York City.