This program analyzes the costs and returns for investing in high speed fans (HSF) on a dairy not presently utilizing cooling strategies. The values which are already filled are default values. You can change these values according to your own situation. Yellow cell values are calculated automatically and cannot be changed.

Income tax rate
Minimum attractive rate of return

Number of fans.			Choosing fan size and number of fans.
Fan horsepower		hp
Efficiency		decimal
Cost per fan	$	$/fan
Total installation cost	$	$/fan
Electricity rate	$	$/kwh
Hours of operation per year
Electricity cost	$	$/yr

Milk price		$/cwt
Number of cows
Gain in production		%
Base milk production		305 day average
Gain from cooling	$	$/yr

Net present worth	$	$
Annual benefit	$	$/yr
Payback		yrs

Choosing fan sizes and number of fans:

Provide cooling fans to increase air movement over the body of the cow. Air should move past cows' bodies at 200 to 400 ft/min. Look for fans that expel air in a fairly tight cone. Typical fans throw air a distance equivalent to 10 times the fan diameter. Space 36-in fans 30 feet apart; 48-in fans 40 feet apart. You will in most cases need to have at least 3 fans (1 fan over the feed alley and two over the stalls) for every 30 or 40 feet of barn length. If you a have a 3 row barn, then you will need 4 fans for every 30 or 40 feet. Use the following table to determine the number of fans you need:

For different size barns, use the analogy between number of rows and length of barn given in the table above to determine the number of fans.

For detailed information on fan characteristics, selection criteria, performance tests, and manufacturer contacts, go to the Agricultural Ventilation Fans Performance and Efficiencies web site from the University of Illinois at Urbana-Champaign.

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