3 school air quality considerations opening a window won’t fix

A national survey by GAO found that 41% of districts need to update or replace HVAC systems in at least half their schools (approximately 36,000 schools nationwide).
Danny White is education vertical leader at Honeywell Building Technologies.
Danny White is education vertical leader at Honeywell Building Technologies.

As this academic year kicks off with in-person learning, and with children in the U.S. spending an average of 1,000 waking hours each year in the classroom, now is the time to focus on schools’ indoor air quality (IAQ). To help build a healthier learning environment, facility managers and district administrators should have the full picture when it comes to their schools’ IAQ.

Studies have shown that poor IAQ can contribute to building occupants experiencing symptoms related to asthma, fatigue, irritation, and headache. With nearly 20% of the U.S. population spending their days inside elementary and secondary schools, prioritizing the quality of air in these buildings is crucial. While you may assume that school infrastructure is well-tended, a national survey by GAO found that 41% of districts need to update or replace HVAC systems in at least half their schools (approximately 36,000 schools nationwide).

Cracking a window is a solution some schools use to improve airflow in classrooms, but it is not sufficient. Airflow is only one part of the IAQ equation.


Government studies have shown that a school’s indoor air temperature can affect the well-being and academic success of students. Low temperatures have been shown to be optimal for airborne influenza survival, with virus survival decreasing the more the temperature increases. On the other hand, researchers have found that higher air temperatures in schools resulted in lower grades on tests that evaluate students’ reading and math skills.

With a potential for problems on both sides of the temperature spectrum, it’s important to have a building management system (BMS) in place that appropriately measures and controls temperature regardless of outdoor climate conditions. A BMS is an efficient way to monitor, manage and optimize the temperature inside a school building to help create a healthier environment.

Humidity Levels

While virtually all schools are designed with heating or cooling equipment that controls indoor air temperature, most older schools aren’t designed with equipment dedicated to controlling moisture. Relative humidity is an important factor in maintaining optimal air quality and comfort for students, faculty and staff. Ideal indoor relative humidity should range from 40-60%. The EPA cautions that high humidity levels promote bacteria and mold growth while exacerbating respiratory conditions, while low humidity levels create dry, itchy skin and upper respiratory conditions. To monitor humidity, school facility managers should rely on IAQ sensors that enable the BMS to make real-time adjustments.


As students continue learning and activities in close proximity, we should expect to see an increased focus on ventilation – with good reason. Findings from a CDC study showed that incidents of COVID-19 were 39% lower in schools with improved ventilation. Effective ventilation includes bringing in fresh, oxygenated air from outdoors and removing stale (or contaminated) indoor air. For facility managers looking to improve ventilation within school buildings, best practices are to avoid shutting down HVAC systems, increase the number of air exchanges per hour to closed spaces and expand fresh air intake to 100%, or the maximum amount possible.

Best Practices

Humidity levels, temperature, and ventilation can be controlled by investing in technology that can support healthier environments, promote better learning and even potentially curb the spread of contaminants.

The task of improving IAQ may feel daunting for some, but in reality, implementing the latest technologies doesn’t have to be costly or time-consuming. Total costs vary depending on the age of the school building, its square footage and other factors, but for more modern buildings with HVAC systems from the last 10 years, these changes can be made for as little as $11-15 per student. Plus, the American Rescue Plan is providing a total of $190.5 billion in relief for K-12 schools, and this funding can be used for HVAC system upgrades.

Opening a window or a door shouldn’t be the long-term solution to improved IAQ. To support the ongoing success of students, teachers and administrators, facility managers must develop a multi-layered strategy that leverages best practices and technologies for IAQ to create a healthier and safer learning environment.

Danny White is the education market leader for Honeywell Building Technologies. He has 25 years’ experience in the building industry. He is a West Point graduate and received his MBA from Georgia Tech.

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