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High-Volume Low-Speed Fans – Keeping Large Buildings Cool

Fans are one of the best parts of summer. Anyone who grew up in a Southern state or survived a late-August heat wave can recall fond childhood memories of sprawling out in front of a box or oscillating fan to keep the heat down, probably making a robot voice. Ceiling fans also ran all night, working to keep your family cool. Now, manufacturers make fans big enough to push air through factories and huge warehouses. The giant-sized versions of the humble home ceiling fan are High-Volume Low-Speed (HVLS) fans. These larger-than-life fans move massive amounts of air with ease.

Having survived the heat of summers long enough to finally become the adult in charge of the thermostat, fans are still an important part of keeping a house comfortable. A good fan can keep cool air circulating to keep rooms feeling fresh and can have their blades “flipped” in the winter to help keep heat where it should be in a space. Now, people have access to the amazing invention that is the high-volume, low-speed fan. Although you won’t find a HVLS in your local home improvement store or as part of a chic home redesign, these fans have a perfect place in keeping tremendous buildings at their proper temperature.


The History of HVLS

High-volume, low-speed fans were invented by Walt and Eddie Boyd, a father and son pair of inventors and product developers. According to their company’s website,, Walt Boyd started his career out as a race car driver with a knack for creating products to improve existing systems. He created things like an efficient tie-down system for trucks to keep cargo safe, huge self-elevating jumbotrons for sports events that could lift themselves up for a crowd to view, and a machine that could pick grapes at night so that the fruit stayed cool and arrived fresher to grocery stores. 

In 1998 the University of California, Riverside asked Walt and Eddie to help them cool the barns that housed dairy cattle. Cows, just like us, don’t like to be too hot, and milk production drops in high temperatures. The Boyds set themselves to the task and in the end created a fan large enough to move huge swaths of air to cool the barn efficiently. The installation of slow moving, large blade fans helped make the temperature feel cooler in the barn, which made for happier cows and more milk for the dairy farmers. This was the first HVLS and set the creation and production of HVLS fans into motion. By 1999 there was the first distributor of HVLS fans that would one day become the company known as Big Ass Fans, still in operation today. 

From there, the HVLS market has expanded greatly, bringing innovation and competition to the market. HVLS fans were created for large buildings with a singular open space. Barns, gyms, warehouses, and air hangars can all benefit from the installation of a HVLS fan.


Blades of Glory

So how does a HVLS fan work? Much like one of the ceiling fans at your home, just at a much larger scale and a much lower relative speed. Go Fan Yourself explains that HVLS fans work to provide evaporative cooling. The moving air helps to evaporate sweat from the skin and remove humidity from the air, which can help make a room feel cooler without the need for more cold air from an HVAC system. This makes it far more energy efficient to keep a building at a comfortable temperature. Go Fan Yourself also points out that the constantly moving air can help keep moisture off of surfaces like cement floors, which can be a slip hazard. 

In the winter, HVLS fans help keep warmed air down where it is wanted. As hot air always rises, an HVLS fan can be used to force the air back down and keep a room feeling warmer. This method of bringing warmed air to where it is desired is called “destratification”. That’s because it mixes the naturally occurring “layers” of air in a room. 

HVLS fans are all “big” compared to a normal household ceiling fan, but they do come in different sizes. Across several producers, fan blade size can range from around 8 to 24 feet long. The average height of a male giraffe is 19ft, if that helps you put things in perspective!


Big Fans Keep on Spinnin’

The next time you’re in a big building, look up and see if one of these friendly giants is working hard to keep you comfortable. High-volume, low-speed fans use very large fan blades moving at a slow speed to move large amounts of air to help keep buildings comfortable. They work both in the winter and summer to aid in evaporative cooling to help people feel cooler. They also destratify the air, pushing warm air back down where people can feel it. HVLS fans are an efficient solution to air movement in buildings as a compliment to HVAC systems.

The wide variety of sizes makes them useful for all sorts of different building layouts and requirements of the people, animals, and items inside the building. Everyone, even dairy cows, work better when they feel good, and HVLS fans are a fantastic way to provide excellent air comfort. 

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