I have High Efficiency vents 2 inches from AC condenser. Even though makes for a pretty look, it seems like a bad idea all around. But I can’t find concrete sources to back me up. Please help with URLs to prove my point.
In addition to the potential corrosion concerns, as I see the water vapor I can also imagine continual build up of ice on the the AC fins. Most importantly, with the snow on the AC unit now it seems very plausible that that both the intake and exhaust could get blocked as the snow cap drifts and fills in the area between wall and AC or Vent and AC.