I've seen one in use and in a dry heat it worked reasonably well, though nowhere near as good as air conditioning. In humid heat, so anywhere in the north, they would be useless and as they add water to the air would probably make you feel worse. We just have 12v Sirocco fans.
-- Edited by Meredith on Wednesday 12th of December 2018 02:30:32 PM
I had a chat with the guy at his stand at a caravan/camping show. There's a lot of salesmen at these events, but I have to say he won the award for rudeness and arrogance. I wouldn't buy one from him even if they worked great.