Can I have my intake fan bring in air for under my house or dose it need to be hooked up to the AC? Also how do you have yours?
No, you don't need to be hooked up to AC. Air from under a house is usually cool. What do you have for a grow space and what kind of exhaust fan?
Under the house would be better actually unless its like 40 degrees or 100+. Coming from your AC your going to get sporadic from when its on or off plus adding in the humidity of the AC plus the humidity caused by rapid cooling/warming of the air etc... Only issue you may get I could see from running it under the house would be an open door for any pests that could climb in. this could be fixed with filters/screens etc..