Air Duct Sealing Spray Foam Insulation. Call Energy Guard today at 817-233-0116, to see how we can save you money on your energy bills! Did you know that you may ... Once your air ducts are clean and clear, we offer an air duct lining that will help keep them in that condition for much longer, greatly improving the quality of the air in your home or business. This in-slab air duct lining will prevent the growth of mold and ensure nothing builds up within the ducts so you can breathe better air. Nov 20, 2017 · Two popular methods of duct sealing are in use today: 1. Exterior sealing, usually by hand; 2. Interior duct sealing, using high technology. Howard Air uses advanced Aeroseal duct sealing. An efficient aerosol spray is injected under pressure into the ducts, sealing every crack and crevice from the inside. Home » Blog » How to Inspect, Clean & Seal Air Ducts | DIY Ductwork Inspection. It is important to inspect your air ducts at least once a year. Ensuring your ducts are free from damage and contaminants will improve air quality and the overall efficiency of your HVAC system.