"SBH" wrote in message
...
How do portable AC units compare to their counterpart window units in
performance and efficiency?

The ones I have seen are very expensive and not very efficient. They are not
eligible for the governments energy star program
(http://www.energystar.gov/ia/partner...draft_v2.1.pdf

And the ones I have seen use only a single exhaust vent in the window,
so.... that means you are using your cooled inside air to be blown thru the
condenser and then vented outside to be lost. Not very efficient.