You probably clean the lint filter in your clothes dryer because you don't like the idea...

What happens when you perspire on a hot day? The sweat evaporates, using heat from your body in the process, resulting in a cooler you. This passive cooling system works by the same basic principle: Water is evaporated into hot, dry air, causing the air's temperature to drop. A fan is employed to distribute the cool, moistened air around a room or building. Evaporative cooling systems, sometimes called swamp coolers, are very effective in arid climates, and can use as much as 75 percent less energy than standard air conditioners. They are less effective as humidity rises.

Mold isn't just a patch of blue to indicate your bread's gone bad. There are molds that grow on...