A friend of mine is very impressed with my Prius but hates a/c and wondered about adding a sunroof. I told him it would foul up the aerodynamics, as does leaving the windows open, only more so. Any comments?
04 White #6 3300mi
I have a Camry with a sunroof, and miss having it on the Prius. However, an aftermarket sunroof might be difficult to install on the Prius, considering the limited internal headroom and roof square-footage (not much room for the roof to retract). I suppose that one that slides up and out (looks like an external wing) might work, though. But, down here sunroofs and moonroofs will bake your brains most of the year. They're really nice when cruising in the evenings, though.
I am sure that driving with a sunroof and/or windows open must affect the aerodynamics, but any impact on mileage is limited at lower speeds and more pronounced at highway speeds.
I routinely drive around town with the windows open when outside temperatures permit, and have found that my mileage goes up -- probably because the outside sounds make one more aware of what the ICE is doing.
Driving with the windows down at highway speeds is kind of self-limiting. After all, who wants to drive at 80 for an extended period with the windows open... (especially when it's 115 degrees outside!)
On one of the other Prius Forums, Andrew Grant, who drives the older Prius as a taxi in Vancouver reported that the sunroof reduced headroom by 3" but was happy with it. Other users remarked that the headroom reduction was 2". Again, older Prius'.