BEWARE
The cool humid air coming from a AC unit is PERFECT for mold to take hold and eat your grow.

If you use an AC unit, make sure you have a humidity reader and dont let the temps go below 70.

Of course the best way to install a window AC unit is in the window, they are made that way to blow the hot air out, and they leak water outside.

You can buy a free standing AC unit at Walmart usually, just watch for mold.