Skip to main content
Calcimator

Dairy Facility Ventilation

Calculate required ventilation CFM for dairy barns based on barn dimensions, cow count, and target air exchanges per hour.

Inputs

ft
ft
ft
/hour

Results

Required Ventilation

140,000 CFM

CFM per Cow

700 CFM

Barn Volume560,000 cu ft
Winter Minimum CFM3,000 CFM
Summer Maximum CFM200,000 CFM
48" Fans Needed (est.)8
Floor Area per Cow200 sq ft
Est. Monthly Energy Use10,228 kWh
How to Use This Calculator
  1. Enter barn dimensions (length, width, sidewall height) and cow count.
  2. Set the target air exchanges per hour for the season.
  3. Input fan diameter and individual fan CFM rating.
  4. Review total required CFM, number of fans needed, and estimated ventilation operating cost.
  5. Verify CFM per cow meets the minimum for your climate zone and housing type.

How the result changes with Barn Length

Barn LengthRequired VentilationCFM per Cow
24585,750 CFM429 CFM
733256,550 CFM1,283 CFM
1,318461,300 CFM2,307 CFM
1,805631,750 CFM3,159 CFM

What each input means

Barn Length
Interior length of the dairy barn or freestall facility.
Barn Width
Interior width of the barn.
Avg Ceiling Height
Average interior height from floor to roof peak or ceiling. Freestalls are typically 12-16 ft.
Number of Cows
Number of cows housed in this barn.
Target Air Exchanges
Target air exchanges per hour. Winter: 4-6; mild weather: 10-15; summer: 40-60 for tunnel ventilation.

What each result means

Winter Minimum CFM
Minimum ventilation for moisture removal at 15 CFM/cow.
Summer Maximum CFM
Maximum for heat stress relief at 1000 CFM/cow (tunnel vent).
48" Fans Needed (est.)
Based on ~19,000 CFM per 48-inch box fan.

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Barn Length = 400, Barn Width = 100, Avg Ceiling Height = 14, Number of Cows = 200 = 5 input(s) provided
  2. Calculate Required Ventilation
    Required Ventilation
    140000 = 140000
  3. Calculate CFM per Cow
    CFM per Cow
    700 = 700
  4. Calculate Barn Volume
    Barn Volume
    560000 = 560000
  5. Calculate Winter Minimum CFM
    Winter Minimum CFM
    3000 = 3000

Related Calculators

The questions that sit next to this one — chosen by subject, including calculators filed under a different category.

Dairy

Dairy Manure Management

Calculate manure storage volume requirements, daily production, and nutrient content for dairy herd manure management planning.

Dairy

Milking Parlor Throughput

Calculate milking parlor throughput in cows per hour based on number of units, average milking time, and unit change time.

Poultry

Poultry House Ventilation Calculator

Calculate minimum, transitional, and tunnel ventilation CFM requirements for poultry houses based on bird count, weight, and house dimensions.

Industrial Hygiene

Ventilation Dilution Calculator

Calculate required dilution ventilation airflow (CFM) to maintain a target airborne concentration from a known contaminant generation rate.

Dairy

Dairy Carbon Footprint

Calculate dairy operation carbon footprint in CO2 equivalents per gallon of milk, including enteric fermentation, manure, energy, and feed emissions.

More in Agriculture & Farming.