A sudden loss or lack of air flow in several rooms of your home or business could be the result of blockage due to a piece of loose duct liner (insulation). The liner is usually glued and sometimes pinned inside the metal plenum (box). Over time it can come loose and obstruct the air flow coming out of the plenum. A service cover or door can be installed on the plenum to allow access to fix the problem. Please call Air Max Heating & Cooling LLC at 601-939-0015. We are duct commanders.