Well-built and efficient fans and maintenance goes a long way in helping to achieve ventilation needs while keeping energy costs in check on the dairy.
The ventilation system on your dairy housing consumes 20% to 25% of the total energy used on the dairy. However, since air is one of the basic needs to support life it’s not recommended you turn off the fans to save money. What it does mean is you need to be looking at the efficiency of those fans.
Different fans are designed and manufactured for different applications. Tunnel ventilation or cross ventilation systems require a static pressure difference to be created between the inside and outside the shelter. Therefore, to design these systems you need information about fan performance tested under static pressure. When comparing fans for these type applications look for fans with a minimum efficiency rating of 20 cfm/W at 0.05-inches static pressure.
Possibly the best thing you can do to improve the efficiency of your ventilation system is to simply maintain your fans. Poor maintenance, mostly lack of cleaning, can reduce efficiency by as much as 40%. What this means is the electric bill stays the same, but less air is moving in the barn. Those squeaking bearings, flopping belts, and dirty blades and shutters are really just robbing your power. Accumulation of as little as 1/8” of dirt on the fan blades can significantly reduce fan performance. Monthly fan maintenance and cleaning would be best, but at a minimum it should be done three to four times per year.
To keep cows, heifers and calves happy, healthy, and productive requires ventilation throughout the year and often requires fan(s). Depending of the housing type and design this may be as simple as a positive pressure tube in a calf barn for better fresh air distribution during winter ventilation or many large circulation fans in a freestall during summer to help in cow cooling. Making sure you choose well-built and efficient fans and then regularly maintaining those fans goes a long way in helping to achieve the ventilation needs of the shelter while keeping energy costs in check on the dairy.