How to use ac (air conditioner) in summer? I work in it and sit all day in ac for 8 how to use ac (air conditioner) in summer hrs. When I go back home, my bed room is so hot. When I switch on the ceiling fan, all the heat from the roof comes down making room even more hotter. If I sleep without switching on ac, I get sweat. If I switch on ac for sometime and then switch off, even then I get sweat at night and wake up. For this reasons, I switch on ac and leave it running till morning. (approx 8 hrs) so if I am under ac for like 16 hrs, 1. What are the health issues that will come if I sleep under ac? 2. What should I cover when I sleep under ac? 3. What is the simple treatment for ac allergy? Who can help me on this? P.s I am suffering from ac allergy.