Inspect home with modified ductwork. 6 ceiling Returns have been split up and connected to a return chase, filtered at side of furnace. It is evident the furnace is low on return air. Recommend disconnecting chase, and cutting a 2 14x24 return filter grills in living area and dining room to provide adequate return for unit. Would also cut in a base under the furnace and seal off the side the chase is connected to. Ductwork in attic is loosely connected and would need to be properly strapped and screeed together before we could attempt a cleaning, otherwise the chance for the ductwork to come apart while cleaning is high, and we would be unable to clean as much of the ductwork in current condition. Left additional estimates to repair and duct clean, as well as replace the supply ductwork.