I never seen this done but I wanted to share something I did that I noticed a nice amount in comfort to the plants. Before my temps were 86ish. depending on the air outside coming in.. could be 74. But usually in the 80s' I tried a few things, using a box to make an evap cooler. and multi places to move the intake and different exhaust fans.. But the one thing I couldn't figure out is how to keep right under the hood nice and cool. No mater how much air I would have blowing on the plants, the fans just couldn't get the excess heat out of under the hood. So I rigged up my 4in intake to blow right on top of the plants. The way this works is if you lower or raise the light. the intake air will always pump air under the hood... Take a look let me know what you think Hope this helps somebody too. It looks bulky and heavy.. but its really lightweight.. I really need to find a better duct flange.. But this pushes the air from under the hood... It also keeps the plants moving alot.. One thing I have learned is that the more air the plants have coming in. the faster they seem to grow..