I like the Bangladeshi concept - it would appear to use the Venturi Effect to increase the flow of air through the device to achieve the temperature reduction. The 12 degree reduction in temp for the Homedics version is pretty meaningless without knowing at what temperature that reduction takes place. Reducing the temp from 104 to 92 would be an improvement, but a spray bottle full of water might be a better way to keep your body temperature regulated. Swamp coolers do a decent enough job in humid environments, but the county that I worked for in Idaho installed one in a LEED certified building Boise and it was pretty much a complete bust in an arid climate - the staff bought a half dozen box fans and kept the doors and windows open all summer long...