Frequently Asked Questions About Attic Fans
Q. What is an attic fan?
A. An attic fan or power attic ventilator is a specially designed fan for
exhausting hot air from attic space. The fan normally mounts on top of
the roof itself, drawing the hottest air out first while drawing in cool
air from strategically located inlet vents.
Q. Will an attic fan look funny on the roof?
A. No, the fan housing is only 8" high and 22" in diameter.
It can only be seen from one side of the house, normally the backside.
Q. How much power does an attic fan use?
A. Very little, the same as 2 or 3 light bulbs, 250 watts. Much, much
less power than an air conditioner uses to cool the effect of hot attic
Q. How do you operate an attic fan?
A. An attic fan is normally automatic. An adjustable thermostat, which
is included, turns the fan on and off according to the temperature.
If you have a humidistat installed, it turns the fan on and off as
well according to the humidity.
Q. Will the attic fan take air from within my home?
A. No, the air is taken from the outside through the attic vents. Already
cooled air within the house is untouched.
Q. When does the attic fan operate?
A. We set the adjustable thermostat to turn the attic fan on at 100ºF,
and off at 90ºF. If you have a humidistat, the attic fan turns on
at 70% humidity.
Q. What is a humidistat and why would I need one?
A. In certain areas, an attic can become very humid. The attic humidity
can condense and cause a leaky attic. Over 70% humidity, the humidistat
turns the attic fan on to vent out the humidity no matter the season.
Q. What is a firestat and why do I need one?
A. A firestat senses when there is a house fire and shuts off the attic
fan so that it doesn't draw the fire/smoke into the attic. Only the
higher quality attic fans (such as a Jet Fan) have this feature. For
safety's sake, make sure your attic fan has this feature.
Q. Where is the best place to locate an attic fan in the attic?
A. Exact location of the fan does not matter at all. What is important
is the location of the inlet vents. Vents should cause as much cross
flow through the attic as possible.
Q. What color do the attic fans come in?
A. Jet Fan Attic Fans come in the natural aluminum color. Feel free to
paint the dome to match your home.
Q. I don't like ugly vents on my roof or my roof has clay/metal shingles,
what's my alternative?
A. You can get a gable mounted version of the Jet Fans. This is why we
ask what kind of roof you have. You can also get eave vents installed
instead of roof vents so that you maintain your home's beauty (say, the
roof has clay shingles, or is visible from all sides of the home). Please
mention this in the quote as the gable mounted attic fan will have a
high quality Dayton shutter instead of a dome and are more complex to
Q. Will the roof leak after installation?
A. No, the fan has a one-piece heavy metal flashing. The flashing fits
under the shingles above and lays over the shingles below. Water runs
Q. How big is the attic fan?
A. The smaller fan has a 14" blade and moves air at 1200 CFM@0.03SP,
the larger has a 16" blade and moves air 1650 CFM@0.03SP.The smaller
fan is for attics with less than 2300 sq. ft. and the larger fan for
attics 2300 to 3200 sq. ft.
Q. The attic frame rafters
are only 15" (or whatever spacing) apart,
will your attic fan fit?
A. A Jet Fan attic fan is installed on the roof and doesn't go into the
attic. The rafter spacing doesn't matter. The hole cut out for the attic
fan is usually between the rafters.
Q. How much money can I expect to save?
A. Exact savings depend on the style of the house. Generally, the more
ceiling area directly below attic space that a house has, the more
you stand to save. savings after the cost of the fan will be realized
in any house in one or two seasons along with added comfort.
Q. What is a whole house fan?
A. Sometimes whole house fans are called attic fans. However, the whole
house fan is an entirely different concept. Whole house fans draw air
in through the windows of the house and blow hot house air out through
the attic. Of course a whole house fan would never be used simultaneously
with an air conditioner.
Q. I have a whole house fan, do I need an attic fan?
A. We recommend it as you do not operate the whole house fan during very
hot days when you need to run just the air conditioning and have all
the windows closed to keep out the very hot summer air. Your attic
will still heat up, so the extremely hot attic air will need to be
vented out. Do not use your whole house fan as you will be blowing
your cooled house air into your attic. Also, you should NEVER run your
whole house fan without opening your windows to feed the whole house
fan's need for airflow.