Dairy Ventilation Calculator

Enter current conditions

or enter manually

Temperature (°F)

Humidity (%)

NOAA Heat Index (Steadman / Rothfusz)

Milk loss estimates from UMN Extension

Barn location (Wisconsin)

Barn dimensions

Barn width (ft)

Barn length (ft)

Ridge/ceiling height (ft)

Sidewall height (ft)

Herd & ventilation

Number of cows

Air exchange (ACH)

Fan specifications

Fan capacity (cfm)

Fan price ($/fan)

Fan efficiency (cfm/Watt)

Barn location (Wisconsin)

Barn dimensions

Barn width (ft)

Barn length (ft)

Ridge/ceiling height (ft)

Sidewall height (ft)

Herd & fans

Number of cows

Number of fans

Fan capacity (cfm/fan)

Fan efficiency (cfm/W)

Select fan size

60" Fans — VER vs Static Pressure

High

Average

Low

★Your fan

Stars show your fan vs BESS Lab tested fans

Enter your fan performance

Efficiency (cfm/W) at each static pressure

Fan specifications

Fan 1

Fan 2

Assumptions:

Operation: 24 hr/day · Cool season: 6 months · Warm season: 6 months

Electricity rate: 0.1285 $/kWh

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Dairy Ventilation Calculator

Dairy Mechanical Ventilation Tools

About this app

This app was developed by Nilroth Ly and Nesli Akdeniz in Biological Systems Engineering at the University of Wisconsin-Madison.

Contact

If you have any questions or comments:

✉️nesli@wisc.edu

📞(608) 262-0613

References

Akdeniz, N., Bjurstrom, A., Schlesser, H. (2025). Adopting and Evaluating Mechanical Ventilation in Dairy Barns: A Calculator Guide. UW-Madison Dairy Extension.

dairy.extension.wisc.edu/articles/...

Accessed 5-5-2026

Armstrong, J., Janni, K. (2023). Heat Stress in Dairy Cattle. University of Minnesota Extension.

extension.umn.edu/dairy-milking-cows/heat-stress-dairy-cattle

Accessed 5-5-2026

Bioenvironmental and Structural Systems (BESS) Laboratory (2026). University of Illinois at Urbana-Champaign.

bess.illinois.edu/type.asp

Accessed 5-5-2026

Ly, N., Akdeniz, N. (2026). Practical Guidelines to Improve the Sustainability of Ventilation Fan Use in Agricultural Operations. Sustainability, 18(5), 2453.

doi.org/10.3390/su18052453

NOAA. The Heat Index Equation (2022).

wpc.ncep.noaa.gov/html/heatindex_equation.shtml

Accessed 5-5-2026

Biological Systems Engineering · UW-Madison

460 Henry Mall, Madison, WI 53706

Last revised on May 5th, 2026