UnderAire Single Crawl Space Exhaust Fan, 110 cfm


Brand: Tjernlund

Mfr Part#: V1

UPC#: 080956954039

Availability: In Stock
Usually ships: Today, if ordered by 3pm
Qty Price
$57.95 / each & Free Shipping
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Tjernlund V1 UnderAire Series Crawl Space Ventilators are designed to circulate fresh outdoor air underneath home and porches. Is equipped with a factory installed and pre-wired thermostat which will prevent operation of the fan below 35 F. Requires switch or dehumidistat to activate. Multiple ventilators can be controlled by single switch or dehumidistat. Tjernlund V1 ventilates excess moisture, increasis air circulation to fight condensation. Constant operation helps vent radon, treated wood offgassing and odors that might otherwise migrate into living areas.

Choosing between V1D and V2D it is needed first to determine the number of UnderAire Ventilators: 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 V1D ventilators or one V2D ventilator.

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:
- Surface organism growth on floor joists;
- Soil is wet;
- Musty odors in crawl space or living areas;
- Wet insulation;
- Excessive moisture in living areas tending to migrate towards windows.


  • Economy one-fan ventilator;
  • Sealed bearing motor for long lif;
  • Mounts into ventilation openings in block foundations;
  • Thermostat deactivates fan below 40F to avoid freeze-ups.

Technical Specifications:

  • Performance: 110 CFM;
  • Motor: 115/1/60 50/60 Hz 0.30 AMPS maximum;
  • Thermostat: On at 50 F, Off at 35F;
  • Dimensions: 14-3/8" x 6-7/8" x 2";
  • Material: galvanized steel;
  • Finish: aluminum.


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