To determine the correct number of Power
Temp-Vents, use the following formula:
Calculating how many foundation vents are needed.
Multiply the square feet
of the crawl space by the height in feet. This gives the number
of cubic feet in the crawl space.
Multiply the cubic feet in
the crawl space by the number of air changes per hour desired
(4-6 is the recommendation). This gives the total number of
cubic feet of air that has to be moved per hour to produce the
desired number of air changes.
Divide this number by
either 7,200 or 11,160 ó depending on which model is being
used ó to obtain the number of power vents needed.
Install Automatic vents to
provide air intake on one side of the foundation with the power
vents on the other side to create a system of intake and
Example: 1500 square foot crawl space x 3 feet high = 4500
4500 cubic feet x 6 = 27,000 / 7,200 = 3.74
Install 4 powered vents with 4 non-powered intake vents on the opposite side
Power vents should be placed on one side of the house with
non-powered vents that act as intake vents, on the other side.
If installing vent in a below grade foundation, a vent well is
here for vent well information.
Please choose model type below when ordering.
Note: The operation of this temp-vent may be loud when
installed in a wood stud wall. To reduce noise, install in a
concrete or cinder block foundation wall.
Whenever possible, vents should be placed on all sides of the
foundation. This will create an intake/exhaust system that delivers
a steady flow of air. One vent should be installed for each 8 to 10
feet of foundation wall.
Most building codes require 1 square foot of open ventilation
area for every 150 square feet of crawl space. Temp Vent Automatic
Foundation Vents have 50 inches of net free area per vent.
Therefore, you should install one vent for every 50 square feet
of crawl space.
For crawl spaces with polyethylene installed, on 80-90% of the
ground, the ventilation requirement changes to 1 square foot of
ventilation for every 500 square feet of crawl space with a minimum
of 4 vents installed to provide cross ventilation. For crawl spaces
with polyethylene, install at least one vent for every 500 square
feet of crawl space.