When people speak of air conditioning, they usually mean “refrigerated” air, which is the usual form in humid area. With “refrigerated” air, when one turns down the thermostat, the air is chilled and blown into the room or house. Here in the arid west, we use EVAPORATIVE COOLING. This cools the air and humidifies it at the same time, it is more energy efficient, but turning down the thermostat won’t do a thing. The cooler is not controlled by the thermostat. It has a separate control.

The way it works is this:

On the roof of each house is a shallow pan of water, filled by a float valve. When the cooler is turned on, a porous “quilt” of plastic rotates through this pan, picking up water, then rising in front of a powerful fan which blows air through it. When water evaporates, it cools. The resultant cool, moist air is forced down through duct work into your house. An important thing to remember: The air has to have some way to get out of the house or the house and its occupants will get wet enough to grow moss and oyster mushrooms by morning!

In order to work properly, the air has to flow THROUGH your house: IN through the ceiling vent, OUT through any window or door that is open. A couple of inches is enough. If you have a two bedroom house and you want it all to be cooled, you would open a window in each bedroom, a window or door in the living room, perhaps a window the bathroom as well—or turn on the bathroom exhaust fan. The cool air will go through all these rooms on its way out. The side benefit of the moisture is that your skin, eyes, nose, and mouth will not dry out as sometimes occurs when visitors come from more humid climates into our dry, desert air.

Needless to say, if the bedroom window is left open for the air to flow, the bedroom door must be left open as well. If privacy is a concern, cool the room down before retiring, then—if it has cooled down outside, close only the bedroom door. If it is still uncomfortably warm outside, shut the window to hold the cool air in. Remember, however, the air has to get out of the house somewhere, so if you have the cooler on, always be sure a door or window is open somewhere in the house.