Exhausting air outside when using Air Conditioning, yes or no?

Yes, if you are running a fan to pump your air conditioned air outside that puts a greater load on your AC. An equal amount of outside air must leak into the home to replace what you pump outside. So yes, your AC is working harder. The nice thing is you also don't have to worry about smell in the house. But... as Mr. Creepy mentioned you are blowing hot humid air outside. If the air leaking back into your house is cooler and lower humidity it's a good thing because it's easier to condition. If it's hotter and more humid outside then it is making your AC work harder. I have a lung room. It is it's own space with it's own air conditioning. My fan exhausts into the room where the dehumidifier or air conditioner can process the air to be reused. This can be energy efficient but it also means the CO2 in the room can become reduced so nothing is perfect and a solution to one problem often causes a different problem.