How close is the unit to the wall?
If the unit is only inches away form the wall and you are running the exhaust hose out a window, more than likely their exhaust hose bend is at 90°(every 90° bend is equivalent to 3 feet). In order for the unit to run more efficiently and not overheat, it should be at least 1.5 feet away from the wall and the exhaust hose should be at a 45° angle.