It depends, sometimes my tent will get a bit hot even with the A/C on, when its about 1-2 pm my room isnt very cold like it is throughout the rest of the day so i leave my tent open for a couple hours in order to make sure to keep my heat below 85, if i dont run the a/c with the two lights on and my tent closed it will exceed 90 degrees even with my 273 cfm fan, i have about 5 feet of ducting with no bends in it and the 273cfm fan seems weak, even though its more feet than my tent. but if that fan you have it might work better than mine, with the two 600w's running in my tent, i have to have cold air coming in to keep my tent at a decent temperature.