What's Holding Back The National Air Duct Industry?

https://wiki-net.win/index.php?title=3_Common_Reasons_Why_Your_Air_Duct_Isn't_Working_(And_How_To_Fix_It)

In a duct program, most time the evaporator will be in the basement. It adds extra comfort and security to the living atmosphere. Dampness levels seriously make a difference also.