Dunno. When I talked to my roommate about the heat produced by the phone when charging (hes an electrical engineer, so I trust his word more than my random heresay) he said that the processors are designed to operate quite well at temperatures over 100 degrees. Otherwise, anyone in a southern state wouldn't be able to use it, as the air temperature would cause the phone to be that hot by itself, let alone with the phone running. Take from that what you will. What I tend to do is when home or charging I will have the case off, and put it on when I know I'll be leaving the phone on a desk all day (like at work) or I feel like I'll be placing it about somewhere. Do what you think is best for the phone. You did pay for it after all