I don't think pulling air from the attic will work, the 600cfm fan would evacuate the entire volume of air in the attic in less than 10 min and then I would be back to pulling in 40 degree air. I don't like the idea of heating the air that I need to cool the lights, kinda defeats the purpose heh? I mean, it would take a 1k watt heater to keep up plus the 130 watt can fan . . . thats too much extra juice to cool 2 lights.
It takes the burner 1min 45sec to bring the room to 1600ppm on the high setting, and then maintains a min of 1500ppm by running less than 30sec every 15 to 20 min. I don't think the burner is running more than 20 or 25 min total during the 12hrs that the lights are on. I'm pretty sure the dehumidifier can handle this. And I agree, rh does play a role as far as condensation rates . . . high humidity - more condensation, low humidity - less condensation, you're always gonna see some when ramming 40 degree air into 100+ degree air.
I think the cheapest way may be to create a closed loop in my 6" ducting to use the heated air from the lights, just need to figure out a way to regulate the cold outside air into the loop keeping it around 70 degrees or so. It seems that this might be difficult when temps change 10 or 20 degrees. Something like a louvered vent operated by a solenoid that would open and close automatically by a temperature sensor . . .anyone know of such? Looks like I may be experimenting again.
I guess the only choice I have for now is to pull the safety glasses out of the hoods, block off the exhaust inlet and let the mini split deal with the heat. Damn thing pulls over 1400watts and hardly ran during warmer days when I could make use of the sealed hoods and fan. I used to look forward to fall and winter because of the decreased usage in electricity, nothing lasts forever I guess.
Thanks guys.