I know there have been LOTS of these questions, and I have read some of them I promise. But before I go out and spend more money, I'd like some advice on what size fan you all think I should use for my setup. My seeds have germinated, and are about 4 days old.. growing really well. But I don't have a fan or anything in there yet...please help! My setup: Wooden frame box, 4ft long, 3ft high, 2ft deep. I have 4 x 100w equiv daylight CFL bulbs in there for 3 plants. (18hrs light, 6hrs dark) Temp is around 83, humidity around 40% I have attached foil on all surfaces, even floor inside the box. So.. with this setup. I know I need to get a small fan for airflow and temp control, but what about exhaust fan? I was thinking of getting a pc fan, and attaching it to a vent hose, but I am thinking this is probably going to be too small?.. maybe trying to setup carbon filter inside or something.. What with the seeds and supplies.. I've already got about 200 in this project, so starting to get low on cash.. Any ideas for at least a quick band-aid solution?
Here's stuff that helped me: Ventiliation Explained - Part 1 | BGHydro Ventiliation Explained - Part 2 | BGHydro Johnk helped me with a lot of great information. But I don't know yet how it will all work out because I'm still constructing. That info with his info seemed really sound and reasonable though.
Depending on where he is able to mount any vent fan, I think a 6" centrifugal is way overkill for the size he's venting. I've got a 4" in a cabinet that is 70" x 48" x 20" and I'm on the high size there, too. I know more is always better when it comes to ventilation, but a 6" fan on that box is something he probably doesn't need. His temp doesn't need much cooling and humidity looks fine. My 4" fan pushes 170 cfm for just under 48 cubic feet of space, and they say what, you need roughly 1 cfm for 3 each cubic foot of space as a minimum? I could theoretically get away with a 15-16 cfm capacity fan (with minimal ducting). I think the 4" inline duct fans run around 60 cfm or so. I know those 4" inline fans regularly get trashed here, but on that size box, it might be perfect, especially if it won't have any appreciable length of ducting attached to restrict air flow. I'd try one first (you can get them at HD for about $25) and if it doesn't move enough air to cool your temps, you can always take it back in a reasonable time frame and upgrade to a 4" centrifugal, which I'm sure would be more than enough for that box. You'd definitely have to mount it outside the box, though. Just my .02. Good luck.
That's definitely the right price range I'm looking for. How loud is it though? Currently have this box in my bedroom. As for mounting it outside. You mean make sure the actual fan is attached to outside of the box so the tube is kinda sticking out? Sorry for stupid question.. but this is my first time.. learning lots, but LOTS more to learn!
I'm not sure how loud the small in-lines are. I had purchased one, then decided that even though I won't have but 6' of ducting or so outside the cabinet and only a couple feet to the maximum dropped height of my HID light, it wouldn't have been enough to cool the cabinet come summer. I took it back and bought a 4" centrifugal, but I'm now thinking of picking up an inline for just sporadic circulation during winter months. I'm just now putting my cabinet togther, and have to experiment with temps, ventilation requirements, etc. I'm pretty sure I won't need the centrifugal fan druing the winter. I might have to swap them out on a seasonal basis, I'm not sure. You could mount the small inline fan inside the box. I was referering to mounting a larger centrifugal fan. It would never fit in the box and still allow adequate growth space. They're just too big. You'll likely have to wire a 4" inline. If you have an older, dead appliance or something that you can cut the grounded plug (3-prong) and a few feet of cord off, that would probably work fine. If I recall, the wires on the inline I had were black/white/green. A standard grounded plug should have the same colors.