DIY LARGE DUCT INSULATION KIT, (48"x12') RADIANT BARRIER USING REFLECTIVE FOIL WRAP Stops 97% of Radiant Heat Loss,Saves Energy,Helps Lower Utility Costs.HVAC Systems can lose up to 30% of Heating and Cooling through Duct work! Good Air Duct Insulation Will Improve the Energy Efficiency of your Home and Save Money. Prolongs the Life of your Furnace and helps maintain proper Air Distribution throughout the house. Patented 3/16" Reflective Foil with a "Class 1/ Class A" Fire Rating.Non Toxic,Non Carcinogenic,Fiber Free.Enviromentally Safe.Resists growth of Fungus,Mold and Mildew.