How much ventilation is *actually* needed?

I just bought a Saturn 4 Ultra 16k and im thinking about places to set up. I do intend to get a grow tent in eventuality but thats not in the picture for right now.

Ive got a spot next to my window that opens up to ground level with an air vent directly above it. I was going to put it on a plastic fold-out table there since very little light gets in but it could give decent ventilation with a fan next to it.

Is that enough or should I just move it to the garage? My issue with the garage is thats where my fridge is and theres absolutely 0 airflow and its hot as all get-out in there. I feel the garage is just going to turn into a musky fumey gas-trap.

Advice?