回複：your furnace not gas force air?

Maybe I don't understand the detail of HVAC, my heat is gas, and AC is electric, they are totally different system. I don't know if there is any furnace in my AC unit, only see one machine on top of my bathroom and one condensor outside of the house. (actually the bedroom is new addition to the old house, so living room/kitchen has one AC, and bedrooms has another AC unit (I guess that's why the air handler is in my bathroom). Not sure if I explained clearly. Thanks so much JY, I learned a lot from your posting!