Indoor air quality is important whether you work in a warehouse or a barn. Indoor air, when it isn’t continuously mixed with fresh air, becomes stuffy and smelly.

With high ceilings and vast storage areas that are in constant flux due to stock movement and distribution, large warehouses face ongoing ventilation and temperature battles.

Natural ventilation can help maintain good air quality, but this presents numerous other natural challenges – namely, it’s difficult to maintain a uniform air temperature. And while HVAC systems and box fans can help with distributing air and maintaining temperatures, they consume vast amounts of energy and are expensive to run. Plus, you’d need numerous box fans to cool down such a large space, which can become a hazard.

To maintain indoor air quality and increase the comfort level and productivity of employees, high volume, low speed (HVLS) large-size commercial ceiling fans should be looked to as an efficient and cost-effective solution.

Challenges of natural ventilation systems

Natural ventilation is ideal; however, these systems come with their own inherent challenges.

Maintaining uniform temperatures is difficult
With a natural ventilation system, you must constantly monitor humidity and temperature. In the summer, it can be difficult to cool down the interior of a large warehouse if a breeze isn’t blowing. If you live in areas of high humidity, opening doors and windows is simply not an option. In the winter, it may be too cold, yet keeping them closed causes heat build up.

Building must be oriented correctly
To take advantage of prevailing natural conditions, a warehouse must be oriented correctly. However, this is not always possible, given individual outside terrain and logistics considerations. The area around the warehouse must be free of obstructions to allow for the free flow of air, while storage inside must be conducive as well.

Build up of condensation
On high humidity days, water vapor is released into a building. Water vapor moves independently of air and always flows to the coldest point, such as concrete floors, which cool down at night. Once the concrete slab reaches dew point as temperatures increase, condensation is formed on the floor, which poses real safety hazards to people and machinery.

Condensation on roof beams can also drip to the floor and surfaces, causing discomfort for people, and damage to machinery and materials.

HVLS Fans Provide Superior Ventilation

HVLS fans work in tandem with natural ventilation or HVAC systems, and also reduce or eliminate many of the challenges associated with these systems while offering significant energy efficiencies and significantly lowering HVAC costs.

By continuously mixing incoming fresh air with stale air, HVLS fans minimize the total amount of ventilation required to achieve adequate air quality, and uses less energy. HVLS technology also helps keep employees comfortable, safe and productive, and with balanced and controlled temperatures, product and machinery are also within an optimal environment.

How HVLS fans work
For some people, the slow movement of an HVLS fan is deceptive — how can such a slow moving fan cool down employees or provide superior ventilation? You don’t need a physics degree to know that a breeze moving across your skin on a hot day feels good, especially in humid environments.

While a cool breeze brushing over hot skin feels good, high volume air movement can be both unpleasant and disruptive. And, air speed beyond four or five mph usually offers little, if any, additional cooling benefits.

The reason why a large, slow moving fan actually cools better and more efficiently than a small, high-speed fan is due to the large column of air, “traveling” farther than a small one.

Through HVLS technology, when the down column of air from an HVLS fan reaches the floor, the air turns in the horizontal direction away from the column in all directions. The air flowing outward is called the “horizontal floor jet.” Since the height of the floor jet is determined by the diameter of the column of air, a larger diameter fan naturally produces a larger air column and thus a higher floor jet.

Smaller high-speed fans are incapable of producing the same effect.

Airspeed, combined with fan “effectiveness,” means that very large, low-speed commercial fans are enormously more efficient and effective than small high-speed fans.

Benefits of Using HVLS Fans in Barn Applications

HVLS fans impart a number of benefits to business owners and facility managers including lower energy costs. In addition to supplementing natural ventilation or HVAC systems, HVLS fans also reduce or eliminate inherent challenges.

Improved ventilation and indoor air quality
Although a building, including a warehouse, may have an air exhaust system in place, these systems often fail to thoroughly mix all of the inside air. This type of system gets short circuited as doors or windows are opened and closed. Air pressure created in the suction of the exhaust looks to the path of least resistance and circumvents the intake devices. HVLS fans eliminate this problem as they continuously mix incoming fresh air, vastly improving indoor air quality.

Eliminate condensation buildup
Because HVLS fans constantly mix air from roof to floor, a constant state of thermal equilibrium exists inside the building – and hence, condensation doesn’t form on the roof beams or floor, eliminating condensation dripping on product or machinery, as well as helping to ensure the floor stays dry and safe.

Provide heat destratification
In the winter months, when “warm air rises” the effect can cost an additional 25 percent or more since more heat is required to maintain floor level temperatures. Why so much? The rate of heat loss or transmission through the roof accounts for roughly 70 percent of the transmission losses inherent in all structures. The objective, then, is to even out the temperature gradient from floor to ceiling in order to reduce heat loss.

The unique feature of HVLS fans is that they can run in reverse, which pushes the warm air at the top of the structure down to the floor effectively and efficiently evening out temperature throughout the warehouse. The result is that one HVLS fan applied to 20,000 square feet of indoor space can easily return 20 percent of heating energy dollars.

How to Choose the Right HVLS Fan

HVLS fans are incredibly energy efficient — one HVLS fan can replace up to 50 high-speed box fans while covering up to 20,000 square feet of facility space.

Which size HVLS fan should you choose? This depends on the size of your facility and its height. To maintain continuous air exchange, add one HVLS fan per 20,000 square feet of space. The bigger the HVLS fan, the more air it can move over a larger space.

MacroAir, originator of the HVLS technology in 1998 as a solution for cooling dairy cows and increasing milk production, today remains a leading manufacturer of HVLS fans in 8’ to 24’ in diameter. The company provides a number of calculator applications on its website that, upon entering specific building specifications, help determine the right MacroAir fan (or fans) to achieve optimal air movement and results:

MacroAir fans using the company’s patented 6ixBlade™ technology have proved to lower heating and cooling costs by as much as 20 percent in a variety of building settings. 

Since developing the first HVLS prototype in 1998, MacroAir continues to serve as an HVLS industry leader through its commitment to innovation and design of the most durable and cost-effective commercial ceiling fans on the market. As the “engineers of air,™” MacroAir produces energy-efficient, long-lasting HVLS fans that can be found in barns, warehouses, manufacturing plants, airplane hangars and retail establishments across the U.S. and around the world, and are used by companies such as Coca-Cola, CSX Transportation and NAPA Auto Parts. The company is the exclusive HVLS fan supplier for independent auto dealerships of BMW, Chrysler, Ford, General Motors, Lexus, Mercedes-Benz, Nissan and Toyota under their Dealer Equipment Programs. To learn more about the HVLS industry and MacroAir’s line of HVLS fans, visit or call 866-668-3247. Find the company on Facebook, Twitter and YouTube, and engage with MacroAir experts via LinkedIn and Google+.

–by Eddie Boyd, president of MacroAir


 Big industrial warehouse cooling fans.


 Commercial warehouse ceiling fans.


 HVLS cooling fans keep this warehouse comfortable.