Heat is my biggest enemy with my cabinet-in-a-closet system...

I have an air-cooled 400 watt light in a relatively small cabinet, and the cabinet is a bitch to keep cool. I'm trying different variations on ventilation with a 6" vortex fan and a 265cfm squirrel cage fan. I also have a thermostat and variable speed controller for the vortex fan. A window AC unit cools the ambient air in the room.

The idea is that the room is kept cool with the window AC unit. When the box warms up, the vortex fan kicks on, pulling cooler air from outside the closet and venting the warm air to the attic or outside.

I may use the squirrel fan to cool just the light. I'm also considering an attic fan to cool the attic...

I'll try to remember to post the details of my final setup.