We get this question all the time. People want to know if there is a portable air conditioner that doesn’t need a window for venting.
We hate to disappoint you, but there isn’t a portable air conditioner on the market that doesn’t need to be vented. In fact, all portable units have to have some way to disperse the hot air. Normally, this is done through a venting hose (like a dryer hose) that is placed through a window or door.
If you’re sure that you’ve seen a ventless portable air conditioner, it was probably an evaporative cooler that you actually saw. These look like portable air conditioners, but work in an entirely different way. Also, they don’t require venting. But an evaporative cooler is totally useless if you live somewhere humid. If you live in the desert, you can probably get away with it.
The Air Conditioner Guide 