A whole house fan quickly pulls
large amounts of fresh cool air from the outside through
the house and pushes all the hot air out the attic in
minutes. If the temperature outside drops from
85-degrees to 75-degrees in two hours, for example, the
air in the house will take about four hours to drop that
This fan can do the job in less
than half that time. Since it pushes air out the attic,
it also cools the attic and reduces heat gain in the
house. So by turning on your fan in the cool morning
hours, you can bring in comfortable air, then close up
the house and avoid the searing heat of summer. Turning
it on again in the evening ensures all day comfort on
all but the very hottest days.
The operating cost is about
one-tenth that of air conditioning, according to
Consumer Research. Using this type of fan instead of air
conditioning continuously can cut your electricity usage
by 80 percent. The fans typically draw 400 to 600 watts
of electricity, operating for eight cents or less per
hour, according to Consumer Reports magazine. Therefore,
under the right circumstances a whole house fan can
ventilate an entire house on the electricity an air
conditioner would use to cool one room.
A whole house fan will allow
you to run your air conditioner far less often during
the day. It is the same principle as getting into a hot
automobile: It is much more efficient to open the
windows during the first few minutes of driving to push
the hot air out than it is to turn on the air
conditioner to cool all that hot air.
With a whole house fan, you can
cool the house with fresh outside air in the early
morning, turn on the air conditioning later in the
morning to simply maintain that temperature, then shut
if off in the evening once the outside temperature drops
enough to turn the whole house fan on again. You will
find this much more economical than running the air
conditioner all day long.
NOISY? That depends on
the type you use. Direct-drive fans, which mount the fan
blades directly under the motor and are attached to the
motor shaft, can be quite noisy. Belt-driven fans are
much quieter. They also create higher air flows than
direct-drive models, making them much better suited for
medium to larger houses.
The quietest, most efficient
whole house fan for bigger homes has six blades and
spins at 300 to 500 rpm to make a purring sound no
louder than the typical air conditioner fan.
SIZE? Fans range from 24
to 36 inches in diameter. You must tally the number of
cubic feet of space, excluding closets, store rooms and
the attic, to determine which size you need.