My question is about fans . I have built a room on the patio its 4x8x7. Im going to need intake and exhaust fans. I see a lot of people talking about computer fans. What ,if any, advantage is there to using a pc fan over say one of those 4'' ecoplus fans.

If you have a small space that doesn't have heat issues, it is cheaper and pretty easy to use computer fans. What kind of light do you plan on using?

When you say "cheaper", do you mean the cost to buy them or the cost to run them?

both. PC fans are cheaper to buy and cheaper to run but they do not move a lot of air around.

If you are using CFLs, you might get away with using PC fans but if you are using HIDs in that size space (about 224 cubic feet) - I would get a vortex-style fan that is rated at least 3 times the cubic feet of your room (another words a 672 CFM rated fan or more).

In my opinion, that is far too large a space to circulate air using PC fans. And I wouldn't even consider using PC fans if you're using HID lights in any size area.

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to buy. I would guess that the computer fans are cheaper to run also.

I thought they might be cheaper to run, because they are 12v. What about a blower fan for a boat? Those have good flow, 100 to 300 cfm, depending on the one you get, and those are 12v.

considering your space will require HIDs the cost of the fan is going to be a drop in the bucket.... just something to consider.

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What i'm saying is the cost of the fans will be insignificant when compared to the cost of running the lights.

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On that big of a space Im sure it would be better not to use computer fans. You would have to rig up more then one and it would be a ton of work and I think a waste of your time. Just get the right fan for your space in my opinion.

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The cost to buy the fans is not as important to me as the cost to run them. Dont get me wrong, I cant afford those $300 super blowers, but the cost of running them day in and day out could really add up. 12v fans seem like they woul be cheaper in the long run. Assuming they'r enough air flow.