I just installed a Goodman Gas furnace (downflow) with the coil under the furnace. I'm wondering what is the best way to seal the seam between the furnace and coil as there is a decent amount of air leaking out. Ideally i assume there would be some sort of transition made up between the two but in this case space is at a premium (low ceilings)
should I use some sort of foam? silicone? metal tape? duct tape?