Has anyone tried one of those room cooling units in the summer? Do they really work?

They work in a very small area. The waterless is nowhere nearly as effective as the portable AC units that you pour water into but those need to be backed up against a window or they make the room very humid.

Those “room cooling” units aren’t really air conditioners. They work by adding chilled water to the air. That works fine in a dry desert environment. But anywhere else, it just makes the room clammy and humid without bringing the temperature down much.

Forget the water cooler and buy a room ac. You will not be happy with a water cooler and you will still be hot.