- Don't intake thru the hood- The point of coolable fixtures is that you can remove the heat from the room. Intaking thru the hood will just blow the hot air into your room. If you're going to use an AC, you'll be best served by using a completely seperate circuit( intake->fan->hood->exhaust). Putting the fan inline before the hood will keep the temperature of the air passing thru the fan lower, which will keep your bearings happier.

As I understand it, you'd be pulling cool unsmelly air thru the hood and smelly air thru the filter at the same time with the same fan. Watch out for stinky room air being pulled thru voids in hood, and blowing out your exhaust untreated. Your better off running the hood @ positive pressure- If you really want to do hood and room with one fan, go filter->fan->hood->exhaust- If a little scrubbed air goes back into the room from the hood, it's no big thing.

I'd run a seperate circuit for the hood- it'll take a lot of load off of your AC. Power savings will pay for second fan within six months- and I shouldn't have to mention that security is priceless.

Hope this helps- lemme know if I can help with anything else.