Imo if your just harvesting for personal reasons i would highly suggest just a 600w epistar led. Can get it pretty cheap and can do like 3 plants under it efficiently. as for your venting question just put an inline fan in your room ether 4,6, or 8 inch and take out air from the room but you have to make sure your bring as much air in as your taking out. or you will get brown spots and the bottom of your plant even without deficiencies and you will hate yourself for it. good luck buddy.