[jeff5may]

Looks like you could stand to run some of that hot attic air straight into the airtap. It would definitely boost the cop of the unit, while offsetting some of the cooling of basement air. Literally moving the hot attic air into your water heater at high efficiency. Maybe a couple of lines in the plc code to run some warmish, more humid air towards the unit for more latent/less sensible heat removal? Hot, humid attic air turns to cold condensate down the drain rather than cold, dry basement air...