As I’m starting to peck away at my build again, the A/C question is bouncing around in my head again as I mentally spool up. Any feedback for cutting the heat exchangers out of the air handling sub frame in the WRX, and placing them side by side with a fan mounted on each one to blow through into a plenum for mixing and distribution to vents (aka, sheet metal box)? Rather than one fan control followed by a slider, two fan controls, one for hot, one for cold. Achieve a desired mix by varying each fan speed. I imagine using the factory setup for air so the background stuff (compressor control, radiator fan control) is already integrated, but make a new circuit for heat (matching control switch, resistor module, fan). I’d want the fan control switches to match, so may have to sort through either a new switch to run the oem A/C, or looking at the factory switch to see if it’s a traditional setup to control the heat with a second sourced matching fan switch. Perhaps a gravity assisted rubber flap (like a dryer exhaust) at each heat exchanger’s output to prevent backflow if only one fan is running. And for any married guys, perhaps mount the heat on the passenger side, A/C on the driver’s side, and install a butterfly valve to split the plenum to give her heat and you A/C, lol. It’ll be a bit before I act on anything here, but figured if we start the conversation now, more heads involved would either help sort out or simply point out the problems with the idea. I envisioned something like an add-on heat unit for a UTV, just with 2 parallel blowers and a baffle or two to encourage mixing. Without digging out the WRX blower unit, I assumed 2 new blower fans.

It still requires having longer A/C hoses to be made, but allows for much of the factory stuff to be used like compressor, condenser, always open heat exchanger, etc.