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.

Reducing Data Center Energy Costs: How HVAC Optimization Cuts Carbon Emissions

Ava Montini
Jan 28
4 min read

Data centers are the invisible engines driving our digital economy, supporting everything from video streaming to cloud computing and e-commerce. However, they have an enormous energy footprint. In particular, cooling systems—designed to prevent overheating and ensure server performance—are among the most energy-intensive components of these facilities.

By examining the nuances of cooling challenges, the role of HVAC filters, and real-world solutions, let's explore how data centers can significantly reduce energy costs and carbon emissions without compromising performance.

The Energy-Intensive Nature of Cooling in Data Centers

Walk into a typical data center, and you’re greeted by the constant hum of servers, each generating heat as they operate 24/7. Managing this heat load is critical to prevent server failure, downtime, or even catastrophic equipment damage. Yet, cooling systems, while essential, consume a staggering amount of energy.

Why Cooling is So Energy-Intensive

Relentless Operation
Unlike commercial office buildings or industrial facilities, which have peak and off-peak times, data centers require continuous cooling. The need for uninterrupted service means cooling systems operate at full capacity 365 days a year.
Dense Heat Loads
Modern servers pack immense computational power into small physical footprints. As server density increases, the amount of heat generated per square foot skyrockets. High-density data center racks can indeed generate heat loads exceeding 30 kW per rack, while traditional systems typically range between 5 to 10 kW per rack. This significant increase in power density presents challenges for cooling and energy efficiency.
Cooling System Inefficiencies
Many data centers still rely on older HVAC technologies designed for less demanding environments. These systems often lack advanced features like variable-speed drives or intelligent controls, resulting in wasted energy.
Air Distribution Challenges
Poorly designed airflow management leads to inefficiencies. Hot spots in the server room can force cooling systems to overcompensate, driving up energy use.

The Scale of Energy Use

The average data center consumes between 10 and 50 megawatts of power annually, with cooling alone accounting for 30-40% of this usage. According to the Uptime Institute, cooling inefficiencies represent one of the biggest opportunities for energy savings in data centers.

Filters

The Overlooked Hero of HVAC Efficiency

When it comes to cooling system optimization, much attention is given to technologies like liquid cooling or airflow containment. However, the role of air filters is often underestimated. These small, replaceable components significantly influence how efficiently HVAC systems operate.

How Filters Impact Energy Consumption

Filters are designed to trap particulate matter, dust, and contaminants, ensuring clean air circulates through data centers.

However, not all filters are created equal:

High-Resistance Filters: Traditional pleated filters create substantial resistance in airflow, forcing HVAC fans to work harder to push air through the system. This increases energy demand and operating costs.
Low-Pressure Drop Filters: Advanced filters with low-pressure drop technology reduce airflow resistance, enabling cooling systems to maintain efficiency while consuming less energy.

The Domino Effect of Poor Filtration

Using inefficient filters doesn’t just waste energy—it creates a ripple effect of operational problems:

Increased Wear on Fans and Motors: Higher resistance shortens the lifespan of HVAC components.
Hot Spot Risks: Poor airflow management leads to uneven cooling, forcing systems to overwork.
Dust Accumulation: Ineffective filters allow particulate matter to settle on server components, increasing the risk of overheating and equipment failure.

Real-World Benefits of Optimized Filters

Implementing advanced filters tailored for data center environments yields measurable benefits that go far beyond energy savings.

1. Energy Savings at Scale

Switching to low-resistance filters can reduce HVAC energy consumption by, on average, 15%, depending on the system's configuration. For large-scale data centers, this translates to savings in the hundreds of thousands annually.

Case Study
A California data center upgraded its filters and saw a 15% reduction in HVAC-related energy use within a year, saving over $75,000 while cutting its carbon emissions by 300 metric tons—equivalent to planting 5,000 trees.

2. Prolonged Equipment Lifespan

Cleaner air leads to less strain on HVAC systems and server components. Advanced filters trap contaminants that would otherwise accumulate on heat exchangers, fans, and server hardware, reducing maintenance costs and prolonging equipment life.

3. Enhanced Cooling Performance

By improving airflow dynamics, optimized filters eliminate hot spots and ensure consistent cooling throughout the facility. This stabilizes operating temperatures, improving server reliability and reducing unplanned downtime.

4. ESG Alignment and Carbon Reduction

As corporations face increasing pressure to meet environmental, social, and governance (ESG) goals, HVAC optimization offers a practical path forward. According to the U.S. Environmental Protection Agency, for every megawatt-hour saved, data centers can reduce their carbon emissions by approximately 0.4 metric tons.

Beyond Filters

A Comprehensive Approach to Cooling Efficiency

While advanced filters are a game-changer, they are most effective when integrated into a broader cooling optimization strategy.

1. Airflow Containment Systems

Hot aisle/cold aisle containment ensures efficient airflow management by separating hot and cold air streams. This reduces the workload on HVAC systems and improves overall energy efficiency.

2. Smart Cooling Controls

AI-driven cooling technologies can monitor temperature, humidity, and airflow in real time, adjusting HVAC performance to meet dynamic needs. Pairing smart systems with advanced filters amplifies efficiency gains.

3. Transitioning to Renewable Energy

Integrating renewable energy sources, such as solar or wind, with efficient cooling systems further reduces a data center’s environmental footprint.

A Vision for Sustainable Data Centers

The story of data centers is one of both opportunity and responsibility. As the backbone of modern technology, these facilities have an obligation to operate sustainably. Advanced air filtration represents a simple yet powerful lever for change, enabling data centers to reduce energy demand, enhance reliability, and align with global climate goals.

Small changes can lead to big results. Advanced filters, though often overlooked, can redefine the energy efficiency of data centers. Coupled with strategic airflow management and cutting-edge technologies, they are key to transforming data centers into models of operational excellence and sustainability.

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