Duct insulation refers to the practice of adding insulation material to the walls of air ducts. This insulation acts as a barrier, preventing heat transfer between the ducts and the surrounding environment. In simpler terms, it keeps your conditioned air at the desired temperature as it travels through the ductwork.

The best insulation for HVAC ductwork is foil-faced fiberglass insulation with an R-6 or higher R-value. The foil facing helps block radiant heat transfer, improving overall efficiency. Look for insulation specifically rated for use with HVAC systems by Underwriters Laboratories.

Ductwork insulation ensures that air traveling through the duct system will stay at the desired temperature and won't "leak" out. Leaking air results in unnecessary energy loss, which means that your HVAC system will have to work even harder. This will cause higher utility bills as a result of wasted energy … not good for you or the environment.