MacroAir’s founder, Walter Boyd, invented the High Volume, Low Speed (HVLS) fan in 1998 to cool dairy cows to help them produce more milk. Over time, many different fan manufacturers have come into the market, and so it’s important to know the key HVLS fan features you should look for before buying your own.


1. Fan Diameter

The size of the fan you choose will matter. You need to know that the size of your space will help you determine the type of fan that you should buy. HVLS fans come in sizes ranging from 6 to 24 feet in diameter. With so many options, we’ve created a simple graphic to help guide you.


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The graphic above are just some examples of spaces our fans can work in… have a space that is not listed? Do not worry, we have a fan for you!

The general rule of thumb when thinking about the size of the fan is: the larger the fan, the more air it will move.


2. Type of Motor Unit

Both industrial and commercial MacroAir fans have fan lines with direct-drive motor units. One of our industrial fan lines also has a standard gearbox and motor.

The main differences between gearbox-driven and direct-drive motor units are sound, speed and price. This graphic can help you determine which one is right for your space:



3. Speed and Air Movement

The speed at which a fan rotates does not always indicate that the fan is working better. In fact, an HVLS fan’s revolutions per minute (RPM) are much lower than a high-speed fan. This is due to its larger diameter and long blades.

HVLS features a large diameter and slow rotational speed, which is what allows the fans to move so much air. The lower RPM of MacroAir HVLS fans allow them to move large volumes of air at slow speeds.

HVLS fans kill two birds with one stone – you can use fewer fans at lower RPM which uses less power for the same or better air movement.


4. Number and Type of Blades

There are two main factors to consider when it comes to blades:

  1. Number of Blades: HVLS fans come with various number of blades depending upon the manufacturer. What we’ve found at MacroAir is that 6 blades is optimal for energy efficiency and air movement. However, our blades are a specific width and shape that proves more effective than other manufacturer’s 6-blade fan designs.
  2. Shape of Blades: A common misconception is that the number of blades is all that matters. Some HVLS fans have smaller airfoils that move less air or move the air less efficiently. MacroAir fan blades are NASA-inspired airfoils that are slightly wider, moving a larger amount of air more efficiently.


5. Energy Efficiency

HVLS fan efficiency is often measured by how much airflow is generated by the fan per watt of energy used to power the fan. In other words, overall efficiency comes down to moving more air using less energy.

Most HVLS fans are energy-efficient by nature because they move a large amount of air at lower speeds. However, some HVLS fans are more energy-efficient than others. MacroAir fans generally cost a dollar or less to run per day, while outputting a significant amount of air.

Another important thing to consider is your heating, ventilation and cooling (HVAC) costs. By using HVLS fans alongside HVAC systems, you can turn up your thermostat and—due to the excellent air distribution from the HVLS fans—make the space feel just as comfortable while saving a significant amount of energy.


The Verdict

A fan is made to move air, so you must make sure the fan you are looking for has the ability to move the volume of air you need circulated in your space. It can be challenging to figure out what is right for you as some fans move a significant amount of air, but they may be less efficient; while some fans are more efficient, they may move a smaller amount of air.

While all of the factors we’ve mentioned are HVLS fan basics, nothing is more helpful than using our free fan selection tool to determine the right fan for your space:


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