As tempting as it is, we can’t blame indoor air quality (IAQ) issues within schools on the students themselves, despite their habits. Rather, it’s a mix of several contributing factors including humidity and mold buildup, variable climates, toxins released from construction materials and a facility’s age. Furthermore, many new facilities built with energy-efficiency in mind tend to be so airtight that ventilation with outdoor air is significantly reduced, trapping pollutants inside. Unavoidable in most construction projects are the numerous chemicals found in today’s building products, many of which have never been tested for their potential health impacts (Belew, 2010)ⁱ. With the cost of education on the rise, administrators are researching innovative ideas to incorporate energy conservation into their facilities, new and old, to help combat IAQ concerns. The introduction of air movement within indoor environments is proving effective at assisting ventilation systems filter the air as well as curtailing unwanted aromas.  

Large diameter, low speed fans play a large role in improving IAQ by turning the air in the space over several times per hour ensuring good air distribution. This increased air circulation allows for more constant, uniform temperatures that helps inhibit mold growth while the gentle, quiet operation aids in student comfort, fostering a successful academic environmentⁱⁱ.

Cafeterias, gymnasiums, libraries and classrooms are designed to house more students and operate more intelligently than schools of the past, often serving a variety of activities. These multi-use facilities generally create higher occupancy densities and a greater need for air circulation. Hutto High School in southeastern Texas recently built a new 9,350 square foot library with ceilings heights up to 24 feet. West and south facing windows bring in a lot of natural night, and inevitably, much heat as well. Ceiling fans were specified from the beginning as an energy saving device to reduce air conditioning costs and reliance on the 35 ton [rooftop] air conditioning unit utilized in the space. Two commercial-grade, silent operating 8-foot fans were installed, providing comfort to the occupants by circulating the conditioned air within the space. At the same time they help circulate the air brought in through the ventilation system while keeping humidity, inevitable in the south, to a minimum. This results in far more uniform temperatures across the entire library than with air conditioning alone. 

Energy Efficient IAQ

The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) has set standards on the amount of outdoor air necessary in spaces with HVAC systems to counter the off-gassing of contaminants in indoor spaces as a result of flooring, furniture, paint, VOCs and the occupants themselves. Adequate IAQ is typically a concern between 3- and 72-inches from the floor, which is considered the occupant breathing zone.  In a traditional HVAC system in the winter, only about 80 percent of the fresh air brought into a space reaches the designated occupant level which means the system must compensate for the lost air to create a space that complies with ASHRAE Standard 62.1-2007, Ventilation for Acceptable Indoor Air Quality. The addition of HVLS fans to circulate the air down to the occupant level not only helps to keep IAQ levels in check but reduces reliance on the HVAC system. This air circulation also compensates for the insufficient mixing of the supply air and room air, and the natural buoyancy of the hotter air to remain at the ceiling level.   

Angle Of Attack

Effective air movement doesn’t occur simply through fan rotation alone. The type of blades – or airfoils – and the angle at which the airfoils are placed play an important role. An angle of attack approaching 30 degrees or more will increase drag and therefore require a larger motor yet consequently, move less air. This results in increased energy costs and lower aerodynamic efficiency. At the same time, a flat airfoil that is almost horizontal will typically not move much air at all. With that said it is extremely important to choose a fan with 10 moderately pitched, narrow aerodynamic airfoils to achieve efficient air movement without incurring excessive drag. Similar to aircraft wings, airfoils allow for a much smaller energy-efficient motor. To further enhance the efficiency of the airfoils, winglets are added at the tips to help eliminate wing-tip vortices that can induce drag and lower overall efficiency of the airfoils. (NASA, 2004)ⁱⁱⁱ

Improving IAQ is linked to research indicating improved learning and reduced absenteeism among students. According to an October 2006 study conducted by Capital E in cooperation with the U.S. Green Building Council, “The costs of poor indoor environmental and air quality in schools have generally been ‘hidden’ in sick days, lower student motivation, slower learning, lower tests scores, and lowered lifelong achievement and earnings.” The study goes on to say, “There is a large body of research linking health and productivity with specific building design operation attributes,” including indoor air quality lighting levels, airflow, humidity, and temperature.^iv  Silent, efficient sustainability-focused large diameter, low speed fans are an attractive, affordable and immediate solution for all forward-thinking academic institutions as we make our way through the the 21st century.

ⁱ Belew, Rachel R. “Improving the Indoor Air Quality of Schools,” The Construction Specifier, Canada, November 2010, pp. 101. www.kenilworth.com/publications/cs/de/201011/92.html. Source: www.epa.gov/iaq/schools/actionkit.html

ⁱⁱ Visit www.epa.gov/iaq/schools/tfs/guideh.html#Air-Conditioned%20Spaces

iii www.nasa.gov/centers/dryden/about/Organizations/Technology/Facts/TF-2004-15-DFRC.html

iv Kats, Gregory. “Greening America’s Schools; Costs and Benefits” Sponsored by the American Federation of Teachers, the American Institute of Architects, the American Lung Association, the Federation of American Scientists and the U.S. Green Building Council, conducted by Capital E. (October 2006)