Look closely and you can see the hole on the bottom left hand side of the picture. This A/C leak destroyed flooring and trim in home. The home owner had to have the evaporator coil replaced to stop the leaking water into the hall way of their home....
As you can see from these pictures there are two different air flow issues that could be causing your discomfort in your home or business. The supply plenum supplies the conditioned air to your duct work that distributes the air into the living space or work...
As you may be able to see from the picture, a dog chewed into the bottom of this return air plenum which is located in the garage. The furnace being located in a garage area is very common, the furnace platform or return air platform/plenum in this case is one piece....