Thanks for the replies.

I already have a carbon filter and fan for venting and removing odors from the rooms. Was looking at running just the light cooling system via the HVAC. That way the heat from the lights won't be recirculated back into the basement, and thus into the grow room, but instead get circulated throughout the house. Basement stays cooler, so grow room stays cooler.

Drawing the air I'm creating a negative pressure on the supply side, but on the other hand I'm pushing air into the return side, so in theory, at least, there is no gain or loss in the system. However, I'm no HVAC engineer, which is what led me to ask the question.

Any other opinions on this topic are more than welcome. Knowledge is a valuable thing, and it's nice to see people here share what they know. I'm asking questions more that answering at this point, but hope to be able to contribute something back as I learn. Thanks again. :rasta: