An Introduction to Specifying HVLS Fans

High Volume, Low Speed (HVLS) fans are widely used in commercial settings due to their superior performance to provide comfort, energy savings and versatility. When compared to traditional high-speed fans, HVLS fans offer the architect and engineer greater control over the design and implementation of air circulation strategies in large, high ceiling environments.

We will discuss:

1. Efficient temperature control
2. Factors that affect air displacement
3. HVLS project solutions
4. Selecting an HVLS fan

After reading this article, you should understand the benefits of HVLS fans and what factors to consider when specifying an HVLS fan into your project.

Why Commercial Facilities need HVLS Fans

Architects and engineers are faced with the challenge of finding an energy efficient temperature control solution. Creating an environment that is comfortable for employees and doesn’t overwhelm the utility budget can prove challenging.
There are many factors that influence the climate in large facilities:

• High ceilings: contribute to the buildup of heat layers.
• Open bays: allow infiltration of outdoor air.
• Obstructions: act as air flow barriers preventing air circulation.
• Heat pockets: stagnant climate zones or temperature pockets.
• Seasonal temperature swings, high humidity.

Cooling

According to OSHA, a comfortable workplace temperate ranges from 68 to 76 F. Uncomfortably warm temperatures can lead to a decrease in worker output and an increase in errors. HVLS fans can help promote productivity by moving a large column of air, creating a cooling breeze throughout the entire work area. It only costs about a dollar a day to run an efficient HVLS fan, and it decreases the perceived temperature by 8 F!

Heat Stratification

Without air movement, buildings with high ceilings experience heat stratification. This means that temperature layers develop with cooler air at floor level and warmer air at the ceiling.
Temperature increases 0.5 F each foot, so the temperature difference between the floor and rafters of a 20-foot building would be about 10 degrees.

During the winter, HVLS fans can run in reverse to de-stratify and re-distribute the air. This
is particularly effective if you are designing an air circulation strategy that includes an HVAC system. Pairing an HVAC system with HVLS fans will yield a minimum of 20 percent savings on heating costs by increasing warm air at ground level and reducing heat loss through the roof. This simple, yet highly effective solution makes HVLS fans a year-round climate control solution.

Initially the ceiling temperature in the room below is 10-degrees warmer than ground level. As the HVLS fan runs in reverse, it easily addresses the issue of heat layers by de-stratifying the air.