Flu Season Meets School Season: How Smarter Air Quality Keeps Classrooms Healthy

Every fall, classrooms fill with students—and viruses. Discover how smarter air quality strategies like low-resistance filtration, ventilation, and HEPA keep schools healthier, reduce absences, and support better learning outcomes.

Ava Montini

Aug 19, 2025

Written by

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The scene every September

Every September, the school bell rings and hallways come alive again. But as backpacks and lunch boxes make their way back into classrooms, another unwelcome guest tends to sneak in too: flu season.

Teachers know it all too well. The cough that spreads from desk to desk, the hand sanitizer bottles running low by mid-morning, the spike in absenteeism that leaves lesson plans hanging. Parents know it when the inevitable call from the school office comes: “Your child has a fever, please come pick them up.”

It’s a cycle we’ve come to accept as part of the school year. But what if healthier air could help change that story?

Why flu season and school season collide

Respiratory viruses (including influenza) spread more readily indoors, where exhaled particles accumulate. That’s not speculative; CDC/NIOSH is unambiguous that better indoor ventilation reduces occupants’ overall exposure to airborne viruses. CDC

We also know influenza isn’t only about big droplets from a sneeze. People exhale infectious virus in fine aerosols during normal breathing and speaking, which can linger and travel within a room. That was demonstrated in a landmark study that detected infectious influenza virus in exhaled breath from symptomatic adults, no cough required. PNAS Nature

The drier, colder air from the fall and winter cause low humidity, helping influenza survive and transmit more efficiently. Put simply: when we bring students back into dry, tightly sealed buildings, small airborne particles build up and stay infectious longer. That’s the fixable part.

Think of clean classroom air as a budget with three line items:

Dilute what’s in the room (ventilation/outdoor air)
Remove what’s in the room (filtration/air cleaning)
Disable what’s in the room (UVGI where appropriate)

The key is using them together, sized to the space, and tuned to the school day.

What the standards now say and why it matters

Before the pandemic, most schools designed ventilation systems mainly for comfort—things like controlling odours or keeping CO₂ levels down—not for stopping the spread of illness.

That changed with ASHRAE’s new Standard 241, which focuses specifically on infection control. ASHRAE’s Standard 241: Control of Infectious Aerosols changes the target by introducing Equivalent Clean Airflow (ECA)—a flexible, additive way to hit a per-person clean air goal using any combination of ventilation, filtration, and proven air cleaning. That means a classroom can meet its target by mixing outdoor air with high-efficiency filters, HEPA units, and/or UVGI, rather than relying on outdoor air alone. ASHRAE+1

In parallel, CDC/NIOSH and EPA emphasize practical steps for schools: keep systems maintained, upgrade to MERV-13 or better where equipment allows, and supplement with portable HEPA when central systems can’t carry the whole load. CDC+1 Environmental Protection Agency

The evidence that this keeps kids in class

In a study of 162 California elementary school classrooms, illness-related absences dropped by 1.6% for every extra 1 l/s‑person of ventilation. Increasing ventilation to meet the state standard (7.1 l/s‑person) from the average (4 l/s‑person) could reduce absences by 3.4%, gain $33 million annually in attendance-based funding, while costing just $4 million more in energy.
A study across Washington and Idaho found that a 1,000 ppm increase in indoor CO₂ correlated with a 0.5–0.9% drop in average daily attendance, translating into a 10–20% rise in student absences.
In controlled environments, each 500 ppm rise in CO₂ resulted in 1.4–1.8% slower response times, along with a 2.1–2.4% lower throughput on cognitive tasks.
Harvard’s COGfx study revealed that building occupants in green-certified, well-ventilated environments scored, on average, 101% higher in cognitive tests than those in conventional buildings.

“Will MERV-13 break my units?” (The energy/airflow reality)

The honest answer: it depends on the filter you pick and your fan capacity. Research on rooftop units shows that moving from MERV-8 to MERV-13/14 can raise cooling-mode energy use by a few percent if the filter adds a lot of resistance, or it can reduce airflow if the fan can’t keep up. That’s why filter selection matters as much as efficiency.

Not all MERV-13 filters are created equal. Traditional pleated designs often create a higher pressure drop, forcing HVAC systems to work harder and sometimes leading to performance issues. But newer filtration technologies (explicitly engineered for low resistance at high efficiency, like Blade Air's Pro Filter,) are changing that equation. By combining advanced media with optimized form factors, these filters deliver MERV-13 (and higher) performance without the heavy airflow penalty.

California’s Title 24 research reinforces this point: Many modern low-pressure MERV-13 options can maintain pressure drops under 0.20 in. w.c., keeping systems within safe operating ranges. That means schools can improve air quality, meet public health guidance, and stay compliant without sacrificing system efficiency or longevity.

When you factor in the bigger picture—fewer student absences, better cognitive performance, and improved overall school operations—the ROI clearly tilts toward upgrading. Healthier air doesn’t just protect occupants; it protects the bottom line.

How this translates into a classroom target (the ECA idea)

ASHRAE 241’s Equivalent Clean Airflow lets you add up all the ways you’re cleaning air—outdoor air, central filtration, HEPA, UVGI—until you reach the per-occupant target for your space type. It’s flexible, measurable, and avoids unrealistic demands for 100% outdoor air in cold snaps. ASHRAE

A practical approach:

Estimate your current outdoor air (from design or testing).
Add the “clean air” from MERV-13 upgrades (using published efficiencies) and from each HEPA unit’s clean air delivery rate.
If the sum doesn’t meet the ECA target, add another portable unit or rethink your filtration strategy. ASHRAE

What about measurement and transparency?

CO₂ for ventilation

Track a few representative rooms across grade levels and building wings. Persistently high readings during class point to areas needing a fix (dampers, schedules, or supplemental air cleaning). Health Canada’s 1000 ppm residential benchmark is a useful anchor for conversations with families and staff. Canada.ca

PM₂.₅ for smoke days

A couple of low-drift sensors at kid-height in hallways or problem rooms can confirm your filtration strategy keeps indoor levels below outdoors during wildfire events. Health Canada and EPA both recommend this principle. Canada.ca

Bottom line

Flu season doesn’t have to mean higher absence rates and strained HVAC systems. The most effective path is a consistent program: keep ventilation tuned, use filters that balance efficiency with low resistance, and supplement with portable HEPA or UVGI where it makes sense.

Top Energy Grants and Funding Programs for HVAC and IAQ Upgrades in 2024

Ava Montini
Oct 7, 2024
3 min read

In 2024, the importance of improving Indoor Air Quality (IAQ) and upgrading HVAC (Heating, Ventilation, and Air Conditioning) systems continues to grow, driven by increasing sustainability goals and a focus on health and well-being. Businesses, public institutions, and government entities are seeking ways to reduce energy consumption, improve air quality, and meet Environmental, Social, and Governance (ESG) targets. Energy grants and funding programs offer a crucial pathway to achieving these goals while managing costs.

This guide explores the top energy grants and funding programs available in 2024 to support HVAC and IAQ upgrades, providing businesses and institutions with a roadmap to align their operations with long-term sustainability and energy efficiency goals.

1. Federal and National-Level Energy Grants

Federal-level grants play a vital role in encouraging energy-efficient upgrades, helping organizations improve air quality and reduce operational costs. These programs often provide the foundation for large-scale sustainability projects.

The Energy Efficiency and Conservation Block Grant Program (EECBG)
The EECBG Program, offered by the U.S. Department of Energy (DOE), provides grants to states, local governments, and tribal entities to improve energy efficiency and conserve energy. The program supports HVAC and IAQ upgrades, helping institutions meet both energy reduction and sustainability targets.

Learn more about the EECBG Program
The Low-Income Home Energy Assistance Program (LIHEAP)
LIHEAP assists low-income households with energy-related needs, including HVAC improvements that enhance both energy efficiency and indoor air quality. It’s particularly impactful in areas where aging HVAC systems compromise air quality.

Explore LIHEAP Program Overview

2. State and Provincial-Level Programs

State and provincial programs provide targeted financial assistance to help businesses, schools, and other institutions upgrade their HVAC systems and improve IAQ. These programs often include rebates or direct funding to reduce energy costs while improving the health of indoor environments.

California’s Self-Generation Incentive Program (SGIP)
SGIP is one of California’s leading incentive programs for energy efficiency. It offers rebates for energy-efficient HVAC systems, contributing to reduced emissions and improved indoor air quality. This program reflects California’s broader commitment to sustainability and energy independence.

Explore SGIP
Ontario’s Save on Energy Retrofit Program
Ontario’s Save on Energy program provides businesses with financial support to upgrade their HVAC systems, offering incentives for energy-efficient retrofits that improve IAQ and reduce energy consumption. This program is a key part of Ontario’s energy conservation strategy.

Details on Ontario’s Save on Energy Retrofit Program

3. Utility and Energy Efficiency Programs

Utility companies across North America are offering energy efficiency programs that provide rebates and incentives for HVAC upgrades. These programs are designed to lower energy consumption, reduce costs, and improve the overall quality of indoor air.

National Grid Energy Efficiency Program (U.S.)
National Grid offers substantial rebates for energy-efficient HVAC upgrades. This program helps businesses reduce their energy usage while improving air quality and contributing to overall sustainability goals.

Read more on National Grid’s program.

4. Green Building Certifications and Sustainability Programs

Incentives aligned with certifications like LEED (Leadership in Energy and Environmental Design) and WELL Building Standard encourage organizations to upgrade HVAC systems to meet higher standards for energy efficiency and indoor environmental quality.

LEED Certification Incentives
Many cities and states offer incentives for LEED-certified buildings, which prioritize energy efficiency and sustainability. HVAC upgrades are often required to meet LEED standards, resulting in improved indoor air quality. According to the U.S. Green Building Council, LEED-certified buildings use 25% less energy on average, contributing to healthier, more sustainable environments.

Learn more about LEED Certification.
WELL Building Standard Certification Support
The WELL Building Standard focuses on human health and well-being, with an emphasis on indoor air quality. Many funding programs, particularly in urban areas, provide financial support to businesses seeking WELL certification.

Learn more about WELL Certification.

In 2024, energy grants and funding programs continue to provide critical support for organizations looking to upgrade their HVAC systems and improve indoor air quality. These programs offer an opportunity to align with ESG goals while reducing operational costs and improving the health of indoor environments. By leveraging available funding, businesses and institutions can enhance their sustainability efforts and create healthier spaces for occupants.

To explore the available energy grants and funding programs, including regional opportunities across North America, visit our interactive map, where you can find the latest grants tailored to your region and industry.

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