It probably sustains higher temps when operating. I wouldn't worry about it. Might be in your manual, but that's probably still within operating range. I can't sleep in heat either, it finally cooled off here today thankfully (3 weeks of temps around 100); I have a little portable AC when it stays really warm at night to help sleep. Also roll it into the living room to help out when the plasma on a hot day needs something to counteract it