The directions are the hard part. They mix... strangely for air. Bottom-top works well. Mesh front-back works well. Straight air? Mixes in weird ways.I can only say I bought the XL case specifically for a water build, however, looking at the fan locations, if you used the bottom and side for intake, and the rear and top for exhaust, you'd have 6 intake and 4 exhaust fans, which should give quite a bit of airflow for an air cooled system. I'm sure there may be better cases for that, but, I wouldn't think there'd be much issue keeping one cool on air.