ventilation question

The room size is 3'x5'x9' with HID lighting. The doors to the room are by no means air tight when closed fully. Would it be sufficient to cool the HID hood using a duct fan and keep the doors closed all day? The doors would be opened at least twice a day for a period of about a minute or so. Will this provide sufficient ventilation and fresh air for inside the room? I'm thinking because of the size of the room that opening the doors a few times a day would be enough to keep it fresh inside.
Eventually I plan to incorporate some co2 in the room, which is why I rather just exhaust the hood as opposed to exhausting the whole room. Also, I rather just have to buy one duct fan.

Your inputs would be appreciated.... Peace...

Asked son of chong. He said that a room that size could get enough fresh air but you would need to open the doors about 6 times a day for at least 5 minutes each time. Still are gonna need a hella size exhaust fan attached to your hood via tubing. That will help pull fresh air in through your doors too. But you will need fans to make sure that the air inside is always circulating. And something mounted up high in the flower area or wherever the mega exhaust isn't to help suck that stale air over to/by the mega exhaust. Did that help or was it just confusing?

Mogie,

Thanks for the response. I think I got all that. Just a few things... I shoulda mentioned, the intake for the hood exhaust will be coming from a tube that pulls air in from outside of the room. So basically the hood exhaust system is completely isolated from the flower room itself... Thats why, I don't think it will do much for bringing in fresh air to the room. The fan will be a 160 cfm duct fan (not the crappy bathroom duct fans taht you get at home depot). That should be sufficient for two 400 watts, do you think?

I got the fans for circulation covered. Don't think I will be able to open the door 6 times a day though. Does it look like I might just have to suck it up and get another duct fan to take care of the room air and just put it on a timer so that it pulls in fresh air when the co2 isn't running? I really wanted to keep things simple though...

some help.... please... any of those experienced growers out there....

if the seal for the glass cover of the lights isn't great it will help with the negative pressure in the room, but you would need to scrub that air. i'm not sure how much air it would pull through the loosely sealed door. Either Carefully drill some holes into the glass to help with suction or suck it up and buy a second fan.

length x width x height = cf

you want 2-3 times what ever your cf is for ur exhaust fan...if your room is only 100 cf, then you would want a 300 cfm fan...

You are handling the hot air from the lamp very well by removing it using outside air. But that is not helping your plants fresh air needs. You will need an exhaust for that area as well, and an exhaust requires an intake.

The larger the plants get, the more constant fresh air they will need.