We moved into our newly constructed home in March 2000 and have already replaced the evaporator coil on our Trane heat pump once. I just turned on the system (cooling) for the first time this season and we noticed a musty odor throughout the house. Our HVAC technician says the the coil has a leak and showed me a rusty brown substance all over the coil, which leads me to believe that (1) either the coil needs to be replaced again or (2) the entire unit needs to be replaced (technician's recommendation).
What alternative do I have? I am in no way knowledgable in the technical aspects of this unit. Help!