Upon my arrival I evaluated 1 carrier heat pump system. I verified system safety and performance is to manufacture specifications. Flushed and treated the water removal system. Cleaned the electrical cabinet and washed unit using water. Found large air leak in ductwork, sealed spots that I could with silver tape and mastic. Informed customer falling ductwork could end up on heat strips and be a fire hazard. Customer will have a handyman build new supply plenum. No recommendations at this time.