how can i get the most air from my air conditioner with the vent on open or close?

Question

it's a wall unit

Answer 1

the vent on a window unit does one thing and one thing only. it selects where the air to be cooled is drawn from. in the open position it will draw air from outside, in the closed position it will draw from the inside. works the same as a car ac unit.

Answer 2

The vent should be closed for maximum cooling. I know this because I manage an apartment complex and deal with this question every summer. Other than individual AC unit owners manuals, the only link I could find that addresses this is here:
http://www.american-appliance.com/service_pages/window_ac/

Scroll about halfway down the page to the questions
1.) Air for the unit does not feel cold enough
2.)Air Conditioner cooling but room too warm

"Exhaust vent control set at "Open" position." is listed in both questions as probable cause.