This program analyzes the costs and returns for investing in high volume low speed fans (HVLS) 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 the 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 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. HVLS fans move a large volume of air (up to 88,000 cfm) over a large area (up to 15,000 sq-ft) very slowly (at about 200 to 300 ft/min). At standard speed, a 20-ft paddle fan creates a floor jet about 9-ft deep. Space HVLS fans 60 feet apart over the feed alley. 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.

Top