Destratification Fans

Often uneven levels of air throughout a building can compromise comfort. Depending on the weather conditions, this air fluctuation can vary from 10-20 degrees due to air stratification or the layering effect of large pockets of air with various temperatures.

If you have experienced this in your commercial building or multi-level building, regardless of the HVAC system in place, the frustration is real.

What is stratification?

Every building has free space that contains thermal air layers with different temperatures. These layers are called stratum and form gradient temperature from the floor up to the ceiling. As hot air rises, it spreads out across the area and becomes denser. It is often trapped at the ceiling level. When this happens, the floor level becomes cooler often decreasing the temperature by 1-2 degrees every 3-foot increment of height. The higher the ceiling the cooler the floor level.

What does this mean for you? Your HVAC system will have to work harder and cycle longer to warm your space. When the HVAC system cycles down or shuts off, the area becomes cooler quickly — overall rising utility costs and increasing the chance of premature equipment failure.

What Is Destratification?

Once strata or layered temperatures are formed in a room or area and is trapped at the ceiling level, and needs reversed. Destratification is the act of controlling and changing the natural process of thermal stratification. Because the outside weather conditions cannot be controlled, heating, ventilation and air conditioning is used to help with destratification. Often, HVAC systems need help. Destratification fans like HVLS fans and axial fans can help de-stratify the air and help with heating and cooling.

What is a Destratification Fan?

A destratification fan, typically suspended from the ceiling, acts as a ventilation and destratification device. Destratification fans are one of the most effective ways of solving stratification problems. They help circulate the air to provide a more even temperature. Increasing the comfort for the occupants.

When a destratification fan is used at the proper speed and direction, it will push the trapped heated air at the ceiling back down to the floor level. Overall, reducing the temperature differences from the highest and lowest points of the room. Increasing comfort in all areas and reducing energy costs by creating even temperature distribution.

What are the Benefits of a Destratification Fan?

Most generally, we think of ceiling fans or fans in general as a summer commodity. However, the value of a destratification ceiling fan is utilized during the winter months to increase heat. The airflow that is generated by a destratification fan provides the necessary force and circulation to move the warm and hot air from the ceiling back towards the floor. Increasing comfort overall.

When you have machinery and multiple people working in one area, the heat not only radiates from both the machinery and warm bodies. When that heat is mixed with the original heat source can often become too hot. HVLS fans can help not only distribute the warm air across the area and helps keep employees from overheating.

Reduced pollutants for cleaner indoor air

Everyone is thinking of ‘green’ – go green and save energy and the environment. Building managers and owners realize that green code compliance is essential. Stale, stagnant air is full of pollutants that can affect not only their products but their employees as well. Destratification fans can help with air circulation and minimize the risk of sick building syndrome (SBS). Sick building syndrome is often caused by stagnant, polluted air from chemical fumes, volatile organic compounds, pollen, and bio-aerosols. Sick building syndrome typically causes headaches, dizziness and nausea while inside the building and resolve once outside the building. Using a destratification HVLS fan reduces pollutants from sitting at the floor area and increases ventilation, providing better air quality for employees and customers.

Reduce energy costs

With proper installation and used at the appropriate speed and direction, destratification fans contribute to increase energy savings by helping to save up to 20-30% off heating costs for your commercial building or warehouse.

Eliminate condensation

If you have ever noticed water dripping from the ceiling or collecting on walls in industrial and commercial buildings or warehouses, more than likely, it is not a leak; it is internal condensation. Because temperatures fluctuate with colder air comes in contact with warm air, or gets below the dew point level, a build-up of water or condensation happens. Condensation is a health hazard not only for you but for your employees, staff and your product and machinery.

Destratification fans help reduce condensation by circulating warm, humid air that is trapped in the ceiling and pushes it towards the warmer ground.

What are the Types of Destratification Fans?

There are two types of fans used for destratification:

  • Preventative Low-Velocity Blade or Propeller Fan– Just as the name implies, these fans prevent destratification before it happens by operating continuously along with the heating system. With large impeller blades or paddles, and slower motor speeds, this type of fan requires less energy compared to standard speed fans.
  • High-velocity axial fan – Reactive fans operate at a much higher speed with airflows relative to the area they treat by pushing the air down to the floor level. Generally, with the temperature set, they can change the temperature difference. Once the temperature reaches the preset level, it shuts off.

Both types are controlled by a thermostat and can work independently of the heating system, or along with it.

What to look for when purchasing a Destratification Fan?

Because of the many different types of fans on the market, it can be confusing on choosing which one that meets your specific need. However, there are two things to consider, fan throw and fan spread.

Fan Throw is the distance air will travel from the fan to the floor. Terminal velocity ranges from 50,100 and 150 feet per minute. Most destratification fan specifications may indicate the Fan Throw at one or all three terminal velocity speeds.

Fan Spread is the amount of space a destratification fan will cover at a certain distance. This is the main thing to consider when deciding where to place the fan.


  • Mounting and ceiling height to minimize air pockets or drafts
  • How many fans needed for the area
  • Installation position for optimal air distribution
  • Easy maintenance access
  • Noise levels
  • The direction of airflow

Where is the best place to install a destratification fan?

The ideal location of installation is in high traffic areas. The space outside of the fan spread should have minimal obstructions from equipment, machinery, or inventory storage that limits the fans’ range from reaching the floor level. As an installation best practice, the fan should be installed away from walls by half a fan spread, and a full fan spread from other fans.

Regardless of a new installation during building construction or retrofit installation to an existing building, it should be done by a professional to deliver optimal performance.

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