Facts to know
about Crawl Space
Ventilation
From Mississippi State University
Extension Service:
■
If soil is damp, as much as 20 gallons
of water per 24 hours can evaporate
into the air in a 1,400 sq. ft crawl
space.
■
Primary causes of excess moisture
include:
●
Surface runoff water
●
Poor ventilation
●
No or poor ground vapor barrier
■
Signs of excess moisture in crawl
space:
●
Soil is wet
●
Surface organism growth on
floor joists
●
Wet insulation
●
Musty odors in crawl space or
living areas
●
Excessive moisture in living areas
tending to migrate towards
windows
TJERNLUND PRODUCTS, INC.
1601 Ninth Street White Bear Lake, MN 55110-6794
Phone: 651.426.2993 800.255.4208 Fax: 651.426.9547
Visit our web site: www.tjernlund.com
Copyright © 2006 Tjernlund Products, Inc. P/N 8500720
UnderAire
TM
Crawl Space Ventilators
Easy to install
Designed and engineered
for years of service
How to determine the number of
UnderAire
™
Ventilators needed:
Galvanized face
plate may be
trimmed if
necessary
Thermostat
deactivates fan
below 40
0
F to
avoid freeze-ups
Ventilators are
installed inside crawl
space behind existing
ventilation opening.
Screws and masonry
wall anchors are
included.
Sealed bearing
motor(s)
Complete details on Tjernlund Crawl Space Ventilators are available from your Tjernlund distributor or at www.tjernlund.com
Models V1D and
V2D have 6'
grounded power
cord
Model
V1
V1D
V2D
Performance 110 CFM 110 CFM 220 CFM
Motor
115/1/60 115/1/60 2 @ 115/1/60
0.30 amps 0.30 amp 0.60 amps
Dehumidistat OFF/ON or OFF/ON or
20-80% RH 20-80% RH
Thermostat Opens at 40
0
F Opens at 40
0
F Opens at 40
0
F
Dimensions
14 3/8” x 6 7/8” x 2”
18” x 9” x 2”
18” x 9” x 2”
Specifications
Models V1D & V2D
Model V1
Models V1D and V2D
include adjustable
dehumidistat
Calculate the cubic area of the crawl space by multiplying the length x width x
height. Divide this number by 15 to determine the minimum CFM necessary to
fully ventilate the space in 15 minutes. Example: 20' wide x 40' long x 3' high
crawl space = 2,400 cubic ft. 2400 cubic ft. ÷ 15 minutes = 160 CFM of
ventilation. Choose two V1 or V1D ventilators or one V2D ventilator.
Other Tjernlund
ventilation products
In-Forcer
™
fresh air and
combustion air
intake fans
automatically
bring outdoor
air into tightly
sealed homes.
Duct Booster
®
fans boost airflow
to hard-to-heat
or cool rooms.
Capacities from
150 to 1,200 CFM.
Optional Model DH10
dehumidistat available
separately
