[retiredguy123]

Originally Posted by Blueblaze

Depends on your situation, but since the air handler is in my garage, I've often thought of just putting a register in the plenum, for occasional use. If your garage is small and your A/C new and a little oversize, it might work year round, just to knock the temp down to the 80's. Of course, you'd need the insulation, regardless, but $15 vs $3000(?) for a mini-split? If it was me, I'd give it a try. Probably totally illegal and you'd have to remove it if you sell the house. So save the piece you cut out, and tape it back in when you move.

I looked at my plenum. If could be done, but would require some ductwork because my air handler unit is inside a closet. Also, there would be no return air. It would definitely be a fire code violation.