I'm going to try it anyway, but...

I wanted to consult with anyone willing to listen to me babble first about my idea.

The idea is to take this fan from an oven range hood and use it as my exhaust fan. I found it attached to the range hood at a home rebuilding/salvage type store for $10. I took the range apart, put the fan wiring back together, and tested it. Wow!

Now I know why it is so important to get a blower/centrifugal/squirrel cage fan (call it what you will) instead of an axial type fan. The axial fan I have been using pushes way more CFM than the blower type fan, but likely loses way too many CFM from pressure drops due to curves in ducts and the carbon filter. Hence, my temps get a little too hot (85 - 90 sometimes). That is with 50 F ambient winter air pouring through an open window.....God save my crop if I can't fix this by summer.

The fan itself is rated 250cfm at .1 wg. It is also speed adjustable, anywhere from 'blow you the fuck away' to 'not so gentle breeze'. I only have a 27cf space for 4-5 plants and a 250watt HPS in a cooltube. The power of the fan will be balanced by my shitty duct work (narrow 3'' PVC, plenty of bends), the fact that it will push air through a carbon filter, and its own adjustability. Only real issue here is that there is no way to just hook my PVC duct up to it, and it will not take a round carbon filter. I plan to circumvent this by building a small box for the fan to sit in - the duct will go into the box, the fan will blow out into a seperate but adjoined box which will be a square carbon filter, based on the same design as a round one (see shitty sketchups).

Some pics as well. Please feel free to chime in with advice, feedback, to inform me that I am an idiot, whatever. I am hopeful about this one though....

Good luck all!

Just looked at some calculations for fan/carbon filter size based on room size and wattage, it looks like this will be sufficient for my needs.

Only question is this: This fan uses 3.5 amps at 120 volts so roughly 420 watts. That is way too much, nearly $30 a month in electric alone. However, I imagine this is with the range light on and fan at full blast. Does anyone think the fan will use less watts if I use it at a low speed and only save the full blast for when it is needed, like hot summer days and whatnot? I imagine it would use less watts, but I have no basis for this thought, just hope that it is true. Any insight appreciated!

Yes the hood will use less power, I would imagine just the fan on high is probably 100-150watts. My 8" vortex fans only draw 350 or so.

I have to wait until Monday to talk to Nutone, but I imagined that was the answer.

I also found a great solution with respect to connecting the square exhaust to a circular carbon filter, and it costs less than $7! I can't wait until the temps get hotter and my existing carbon filter runs out of good carbon, so I can set this up and show you all the pictures of my cheap and efficient DIY cabinet. This little duct will allow me to simply connect my existing carbon filter, which erases the cost of having to build a new one. It also will fit nicely into my cabinet.

http://www.lowes.com/lowes/lkn?action=productDetail&productId=36419-85334-GVL0085&detail=&lpage=none

I talked to Nutone a few weeks back, they confimed the fan will only use max watts with fan at max speed and the range light turned on. I plan on using almost the minimum setting, as I have a small space.

I found a piece of ductwork at Home Depot that will connect the rectangular output of the fan to a round carbon filter. It cost $6. Awesome. Pics will follow.

I ordered carbon online, 5 pounds for $30 shipped. The best deal locally is $14 for 28 ounces....shitty. The carbon is due to arrive tomorrow. If it does, I will plan out what needs to be done and make it all happen Tuesday. The main thing will be to move my flowering plants to darkness in a remote location for the day, as working in the cab will throw off a bit of sawdust.

I will post progress as it happens over the next few days. Lots of work to do....

I've had this up and going for some time now, I even improved the idea significantly. I found a register duct at home depot for $7. It connects the 4'' x 12'' rectangular exhaust to a 6'' circle. I used a 6'' to 8'' increaser and set up my carbon filter onto that. This idea worked out and great, and now I can even keep the window closed and the room at 68 and temps in the cab stay at 78-83 with the fan on the lowest possible setting.

Some pics....