Hawk,
A top corner was framed off in the room and cased. It was slotted at the top about 1.5" below the ceiling to take the highest heat .
A 6" hole (room dehumidity)and a 4" hole (heat from hood exhaust) were made in the exterior of the house, and originally ducted into a dual squirral fan inside.
The original fan,
Installed without casing, as everything was being dry fitted....Upper left it can be seen.
Casing and external switching tee, incase i wanted to recover the heat from the halides in the winter.
2x 5" intake ducts were also put in just above floor height to bring in cool air, one on each side of the room.
The squirrel fan i had already rebuilt some years ago, and seemed to get unreliable recently...so it was changed out.
I was very pleased with the fantech inline (4" 115 CFM)(100% dead silent) fan for exhausting the canopy, and wanted to get another inline for the room exhaust, a freind hooked me up with an 8" elicant one.
This thing just about sucks your adams apple out when its on.
Here it is stuffed in there..was a tight fit.
The canopy exhaust is on 24/7, the 8" is wired to a dehumidistat, and kicks on about once every 4-5 hrs at 45% humidity.
When both are on i would guess a total at about 800 cfm of air is being vented outside.
Marc.