There may be few things more satisfying than a cold glass of milk, but chilly temperatures can wreak havoc on a dairy farm’s operations. 

Just ask Hans Griesen of Griesen’s Family Dairy. He moved from the Netherlands to open the 40-acre farm in 2005. Located in the heart of Wisconsin’s dairy land, the 680-cow operation in Prairie du Sac, Wis., should have been producing lots of product, but Wisconsin’s winter weather was affecting operations.

From November through March, the farm suffered production delays from frozen milking equipment, loss of product and employees who were not too happy about working in the cold environment of the milking parlor. 

When temperatures outside were above 32°F, the parlor was well-served by a radiant floor-heating system that used a 400,000-British thermal unit, stainless steel, 95.1 percent efficient Munchkin boiler from Heat Transfer Products of Scottsboro, Ala. And it helps that each cow produces an estimated 4,000 Btu of heat itself. That was good enough to keep temperatures between 38°F to 40°F, even with two 16-by-8-foot entry doors remaining open. 

Cold milk good, cold cows bad

But when it was cold, the system didn’t work well. 

At first, Griesen tried to supplement with portable, “salamander” style forced-air heaters. That warmed up the entrances, but the units cost $100 a day to operate. They also emitted kerosene odors into the air, which wasn’t good for employees to breathe and presented a fire hazard.

Another idea: Have an employee whose job it was to open and close the two doors all day. That proved too expensive, Griesen said. 

Other options weren’t very attractive, either. He decided strip curtains, which would have allowed the doors to stay open. But they constricted the animals’ movements. Griesen visited a nearby farm to check out an air curtain system, but wasn’t impressed. The system had short lengths bolted to span the wide doorway. The curtain vibrated, was noisy and didn’t provide right airflow to keep cold winds out, Griesen said. 

Gas-fired hot water or steam, and electric heating-coil systems were considered, but Griesen said he felt the milking parlor’s existing radiant heat system was sufficient as long as the cold air was kept out. 

Clyde Conger, a sales manager with Bernie’s Equipment Co. in Holmen, Wis., suggested air curtains from New Castle, Pa.-based Berner International. 

The heat is on

Air curtains feature fan motors, blowers, nozzles and directional vanes with a control package. Properly designed, air curtains “seal” doorways from the weather insects or dust. 

Conger and Tim Spreda of Berner manufacturer’s representative MII Equipment of Milwaukee devised a system that uses two 16-foot-long, one-piece air curtains from Berner’s VSA line. They are mounted above the milking area’s open doors. 

While air curtains usually use a plunger switch after a door opens, the milking parlor’s air curtains are activated by a thermostat near the entrance. 

Conger said Griesen eventually knew what he wanted. 

“Hans had already educated and sold himself on the air curtain concept before we got involved; therefore, he knew exactly what he wanted and had designed the application in his head,” Conger said.

The system is working well, according to Griesen. 

“Some of our co-workers were skeptical as to whether air curtains would solve the problem, but they’re believers now since we haven’t had any more frozen equipment issues,” he said. “One employee took infrared color temperature readings and there was a big difference in temperature inside the doorway with the air curtains on and off.”