The Tjernlund UnderAire Series Crawl Space Ventilators are designed to circulate fresh outdoor air underneath homes and porches. excessive humidity levels in Crawl Spaces is the leading cause of premature rotting of support columns, joists, floors and beam supports. Humidity can promote fungus growth and increased termite activity. Humidity may also cause plumbing failures due to rust and corrosion. Constant operation of a crawl space fan helps vent radon gases, treated wood off-gassing and other odors that might migrate into living areas. All Ventilator models are equipped with a factory installed and pre-wired thermostat which will prevent operation of the fan below 35°F.
- Two fans and large faceplate sized for ventilation openings through block foundations. Also includes thermostat, dehumidistat and pre-wired 6' power cord.
- Ventilates excess moisture, the cause of mold, mildew and wood rot and increases air circulation to fight condensation.
- Constant operation helps vent radon, treated wood offgassing and odors that might otherwise migrate into living areas.
Important: 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.
- For general ventilation use only. Do not use to exhaust hazardous or explosive materials and vapors.
- Mount Crawl Space Ventilator inside the crawl space behind existing foundation ventilation openings.
- Ventilation openings shall be within three feet of each corner of the building.
- Screws and masonry wall anchors are included.
- Dimensions: 18" x 9" x 2"
- Capacity: 220 CFM
- Motor: 2 Motors at 115 Volts ~ 50/60 Hz
- Thermostat: On at 50?F, Off at 35?F
- Dehumidistat: 20% -80% RH Range