How an Evaporative Cooler Works

An evaporative cooler is essentially a large fana swamp cooler can use between 3 to 15 gallons
with water-moistened pads in front of it. The fanof water a day.
draws warm outside air through the pads andA large fan draws air through the pads, where
blows the now-cooled air throughout the house.evaporation drops the temperature approximately
The pads can be made of wood shavings - wood20 degrees. The fan then blows this cooled air
from aspen trees is a traditional choice - or otherinto the house. Small units can be installed in a
materials that absorb and hold moisture whilewindow, blowing cooled air directly into a room.
resisting mildew. Aspen wood pads, also calledLarger units can blow air into a central location, or
excelsior, need to be replaced every season orthe air can travel through ductwork to individual
two, and generally cost $20 to $40 for a set.rooms.
Small distribution lines supply water to the top ofNormal air conditioning is a closed system, taking
the pads. Water soaks the pads and, thanks toair from inside a house and recycling it. For air
gravity, trickles through them to collect in a sumpconditioning to function properly, doors and
at the bottom of the cooler. A small water pumpwindows should be closed. Evaporative coolers,
circulates the collected water back to the top ofhowever, take air from outside the house. For an
the pads. Then the process begins over again.evaporative cooler to work properly, the cooled
Since water is continually lost through evaporation,outside air must be allowed to escape. By
a float valve - much like the one that controls thechoosing which doors or windows in your home
water in a toilet tank - adds water to the sumpyou leave open, you can to help direct the flow
when the level gets low. Under normal conditions,of cooled air to areas where it is needed.