In modern American home heating and cooling of living space accounts for more than 50% of energy consumed. Inadequate insulation or air leakages are leading causes of energy waste in most buildings. Insulation also acts as a good sound barrier, keeping noise levels down. The amount of energy conserve depends on several factors i.e. local climate, the shape and size of building, living habits of residents and type and efficiency of the heating and cooling systems. Heat lows from high gradient to low gradient or from warmer place to cooler place. Polyurethane spray foam is applied by professional using special equipment to meter, mix, and spray foam into right place. Polyurethane foam helps to reduce air leaks. Polyurethane spray foam is the most economical way to fill and close cavities in finished walls. Blow-in insulation is applied with equipment by professionals.