All residential window air conditioners
have a cooling system made up of four
primary components: a compressor,
an evaporator, a metering device and
a condenser. Air conditioner cooling
systems actually remove warmth from
the air rather than cool the air.
the air conditioner is running, the
circulating fan and compressor run
simultaneously. The fan motor has
two fan blades attached to it on either
end. The fan blade inside the unit
continually draws room air over the
evaporator coils, which are cold.
The fan blade outside the unit continually
draws fresh outside air over the condenser
coils, which are warm. Because the
evaporator coils are cold, they cause
moisture in the room to collect on
them, much like a cup of ice water
on a warm, humid day. As moisture
increases, water drips down off the
coils into the bottom pan of the air
The thermostat on a window air conditioner
senses air temperature entering the
air conditioner. As the air entering
the unit reaches the set temperature,
the compressor turns off. The blower
may continue to run depending on the
selection chosen on the control panel.
Digital thermostats work on a similar
principle but display a more precise
Air conditioner selector switches
allow you to choose the fan speed.
If "low cool" is chosen,
for example, the fan runs at a slower
speed. However, the compressor always
runs at the same speed and offers
the same cooling capacity regardless
of fan speed.