Direction to face AC ceiling vents

[Dman214]

We recently had an electrician point out that our ceiling vents were blowing in the wrong direction (towards the room), and that they should face towards the windows (or outside of the house) instead. 

Is that typical? What is the reason for this? Anyone have insight into this or somewhere I can read further?

[Spork]

We recently had an electrician point out that our ceiling vents were blowing in the wrong direction (towards the room), and that they should face towards the windows (or outside of the house) instead. 

Is that typical? What is the reason for this? Anyone have insight into this or somewhere I can read further?

I have always seen them blowing across the room.  I.e., when the vent hugs the wall, blowing away from the wall.

Maybe it makes sense if the vent is up against a window to blow on the window... but otherwise, I'd blow into the room.

[MDM]

For a thorough analysis, you'd likely need a Computational fluid dynamics model of your living space.

As that's unlikely, perhaps a somewhat simpler approach would suffice:
1) Are you comfortable with the current orientation?
    Yes> It ain't broke, don't fix it.
    No> Flip the vent directions.
2) Go back to #1

Having the coldest air sweeping across the warmest part of the house (the outside walls) is likely to cause more heat ingress than if the room air near the walls is warmer.  How your comfort is affected may or may not lead to a different conclusion.

[Spork]

I would also wildly guess the "optimal" solution would flip flop between heat and AC.  In other words, you'd want to blow such that the heat goes down (since it naturally rises) and the AC blows across the top (so that it naturally falls).

I'm too lazy to flip flop my vents twice a year.