VENTILATION HELP!! 600w HPS Closet Grow

So i recently started my 600w HPS closet grow and after the first day im pretty sure im going to have intake/exhaust problems and would appreciate everyone's feedback & suggestions.

So my grow room had a slot in the wall which i decided to cover with a piece of plywood. I cut a ghetto 4" circle in the plywood. On the other side the circle connects with an 80CFM intake fan which is flowing air from the grow room into a carbon filter positioned in the slot. There is also a tabletop fan in the slot positioned to blow air from the filter out another 4" hole which leads outside.

After a couple of hours i decided it might bee too hot for my little seedlings. I havent received my thermometer/hygrometer in the mail so to play it safe i have opened the door to the grow room and have a fan positioned to blow cool air from my bedroom into the growroom.

My plan for an intake was to run 20' of 4" duct from a far away window to the grow room with another 80CFM fan pulling air in.

Not sure if my idea of the intake will work, not sure the exhaust is working too well, worried and would like to fix the problem before odor becomes an issue.

Ive come across some homemade dehumidifiers claiming to regulate temp, not sure if this will help or fix the problem...

Maybe a vented reflector hood or cool tube?

Maybe i could take down the plywood, cut a rectangle and use a stronger exhaust fan(EcoPlus 465 CFM Ventilation Fan) hook that up to the carbon filter and still have the tabletop fan blow the air out the 4" hole leading outside.


Thanks for your help if you have any ideas or suggestions please share links, pictures greatly appreciated.

go with the stronger exhaust fan..that 80cfm is not realy 80cfm because of the carbin filter..and maybe get a cooltube... or try to make one thats what i doing..im ghetto too....good luck and

465cfm or 265 cfm squirrel cage exhaust fan? Not sure if 465 will be over kill or not.. its only 10$ more..

over ventilate and overlight(if thats a word, probably not ) and you will not regret it.

I think the word(s) is VENTILATION, VENTILATION, VENTILATION. Right now the seedlings are just that, seedlings. They WILL grow. Please improve the ventilation, you will not regret it for all the problems you will avoid.