If you take a look behind your bumper cover, I bet you'll find HVAC exhaust vents under there. The ones at the rear of the Insight move about as much air as the dash vents (no surprise there), and they exhaust into my trailing wake.
As to the intake, I bet the vent cowl is pretty cool when the car is moving, but you could spray-paint it gloss white so it doesn't get hot when you park.
