Putting the Healthy in HVAC

In the nearly three years since Covid-19 called into question the healthfulness and safety of the nation’s education facilities, schools and universities have been forced to examine whether the heating, ventilation and air conditioning systems that distribute air through classrooms and other school spaces are part of the problem.

When it was determined that Covid-19 was an airborne disease, the focus became even more intense on the performance of HVAC systems, and many schools earmarked federal Covid relief funds to upgrade or replace inadequate HVAC systems.

But school administrators did not need the shock of a worldwide pandemic to be aware of the less-than-ideal conditions of school HVAC systems and the health problems that the resulting poor indoor air quality could cause for students and staff.

A well-publicized report from the U.S. Government Accounting Office—based on information gathered in 2019, before anyone had heard of Covid-19—found that about 41% of school districts needed to replace or upgrade HVAC systems in at least half of their schools. That equates to about 36,000 schools nationwide.

The Rocky Mountain Institute and Undaunted K12, two not-for-profit groups advocating more sustainable energy practices, are the latest to sound the call for an overhaul of the HVAC systems in American schools.

“What has become abundantly clear is schools need modern HVAC solutions that heat and cool spaces reliably and efficiently, achieve ventilation goals cost-effectively, promote healthy indoor and outdoor air, and comply with the evolving regulatory environment,” the organizations say in “HVAC Choices for Student Learning,” a January 2023 report.

The organizations’ recommendation is “to adopt all-electric high-performance HVAC systems in new and existing schools to achieve positive health and learning outcomes, lower utility costs and minimize climate pollution.”

Improvements needed

The Rocky Mountain Institute and Undaunted K12 reached the same conclusion as the 2020 GAO report. School HVAC systems may be hazardous to the health and safety of students and staff.

“Many schools still rely on old and inefficient HVAC systems or have none at all,” the report states. “In addition to undermining student health and learning, these legacy systems contribute to school energy usage and waste, costs, and air pollution. New technology paired with new financial resources warrants that district leaders reevaluate the opportunity to embrace modern HVAC systems in new construction and existing buildings.”

The report points to evidence that links student health and learning to temperature, humidity and air quality inside a school facility.

“Aggravated asthma, absenteeism, poor academic performance and lost learning time are all real-world consequences when HVAC systems fail,” the report states.

The HVAC systems in most schools consume large quantities of energy while generating significant amounts of pollution.

“HVAC systems are responsible for an estimated 56% of all energy use at schools,” the report says. “With over 70% of K-12 school floor space nationwide using on-site fossil fuel combustion for heating, HVAC systems are significant sources of pollution.”

A modern HVAC system of the type advocated by Rocky Mountain Institute and K12 Undaunted would meet these criteria: “It heats and cools spaces reliably and efficiently; delivers healthy levels of ventilation while also mitigating energy costs; promotes healthy indoor and outdoor air; and positions schools to comply with current and foreseeable regulation.”

Electric benefits

The report identifies several benefits that a school might gain from choosing an all-electric HVAC system:

• Adapts to new cooling needs. “All-electric, high-performance HVAC systems like heat pumps not only provide heating efficiently, they also seamlessly introduce cooling in schools, a strategy for adapting to a changing climate,” the report says.
• Improves Air Quality and Eliminates Combustion Pollution. “All-electric HVAC systems prevent combustion pollution and eliminate the need to mitigate the negative health consequences of burning fossil fuels on site,” the report states.
• Enhances Efficiency. “Whether schools are replacing one system, conducting deep energy retrofits, or constructing new buildings, one high-impact approach to improving efficiency will be selecting all-electric, high-performance HVAC equipment,” the report says.
• Minimizes Health and Safety Concerns. School decision makers have a clear opportunity to minimize the risks associated with carbon monoxide and other gas leaks by choosing all-electric systems instead of fossil fuel burning equipment, the report says.
• Builds energy resilience. “Electrification of school HVAC systems can serve as a first step toward building energy resilience, especially when heat pumps are paired with...weatherization and microgrids,” the report says.
• Mitigates climate change. “Combustion-free heat pumps position schools as climate champions rather than contributors to the carbon and air pollution problem,” the report says.

Big ideas

The report lists what it calls “six big ideas” that schools should keep in mind as they explore HVAC technology:

• Advances in technology enable schools to move heat rather than make heat. Rather than handling heating and cooling separately, and burning fossil fuels to make heat, modern HVAC systems enables schools to use a single technology that moves heat for efficient heating and cooling. Those technologies include different types of heat pumps (air source, ground source and variable refrigerant flow) and geothermal systems.
• Schools that use high-performance filters are better positioned to remove contaminants. “Schools that do not have modern HVAC systems often cannot use the filters needed to reduce threats to human health, so they default to less-effective, short-term strategies like opening windows, or invest in additional equipment such as portable air cleaners,” the report says.
• Schools in every climate can select cost-effective ventilation strategies. “Many equipment types can effectively provide healthy levels of ventilation when properly sized and operated for their climate, but only some are especially well equipped to minimize energy use and costs,” the report says.
• All HVAC systems require ongoing monitoring and adjustment. “Given their mechanical complexity and environmental variability, HVAC systems need regular checkups, replacement of parts, and adjustments to operate optimally,” the report says.
• Good HVAC system decisions are sensitive to context. “HVAC systems are selected, sized, operated, and maintained considering many factors, including building size, building orientation, climate conditions, where the building is located, and the quality of the building envelope,” the report says. “Decision-making around HVAC systems should seek out the full context and make explicit the connections and trade-offs at play.”
• HVAC system account for the majority of school energy use, utility costs and greenhouse gas emissions. “Based on schools’ energy use, we estimate the HVAC systems operational in schools today produce an estimated 23.5 million tons of carbon dioxide equivalent nationwide, roughly the amount emitted by more than 5 million gas cars driven for a year,” the report says.

The report calls on superintendents and other school leaders to develop an understanding of the importance of HVAC systems on student health and learning. They should assess HVAC systems in all buildings to identify which can accommodate all-electric, high-performance HVAC systems; the remaining lifespan for all systems; and upcoming replacement opportunities, including existing central air conditioning units.

Administrators should update their district design standards to require all-electric, high-performance HVAC systems and learn about funding opportunities from federal, state, and local sources, including those laid out in the Inflation Reduction Act of 2022.