As temperatures continue to drop, facility managers prepare for the challenge of maintaining comfortable buildings while minimizing energy consumption. Yet, some of the very strategies used to achieve these goals can compromise indoor air quality (IAQ), resulting in elevated rates of particulate matter (PM), rising CO2 levels, and a greater potential for airborne virus transmission.
Many maintenance and facility leaders already understand the connection between IAQ and occupant health, but research increasingly shows that air quality also affects how well people think. Peer-reviewed studies from February 2025 show that even short-term spikes in PM can measurably impair cognitive performance, and workers are increasingly aware of these risks. A recent survey found that among Canadian Millennial and Gen Z workers, 81 per cent report at least one workplace IAQ concern, and 30 per cent would consider leaving their employer because of it.
The challenge to maintenance and facility teams is clear: winter isn’t just a comfort problem, it’s a performance and retention risk that demands proactive IAQ management.
Why winter conditions degrade IAQ
Winter building operations can create a perfect storm for air quality problems. To prevent drafts and reduce energy waste, facility teams typically seal the building envelope and optimize systems for recirculation. They may also reduce outdoor air intake to maintain indoor temperatures and curb heating costs. While these practices are effective for energy conservation and cost savings, they slow the dilution of indoor pollutants and allow occupant-generated CO2 to accumulate faster.
Extended HVAC runtimes compound the problem. HVAC systems operate on large-scale circulation and can unintentionally pick up airborne contaminants from one space and carry them to another. Meanwhile, without proper humidity controls, naturally drier winter air can push indoor humidity below 30 per cent, creating conditions where viruses can survive longer.
Higher winter occupancy further complicates the situation, allowing respiratory droplets to be spread more easily during cold and flu season – and these factors combine to make IAQ more difficult to manage during the winter months.
Immediate, cost-effective solutions
Facility managers don’t have to choose between maintaining good IAQ and energy efficiency. Several practical interventions can improve indoor air without significantly increasing operational costs:
Maintain optimal humidity: Keeping relative humidity between 30 and 60 per cent reduces PM suspension time and creates less favourable conditions for virus survival, while creating more comfortable conditions for occupants. Many buildings already have centralized humidity controls that simply need seasonal adjustment. For buildings without it, portable humidifiers in high-occupancy areas can provide targeted improvement. Monitor levels closely, however, as excessive humidity can promote the growth of mould and mildew.
Upgrade HVAC filters: Moving to MERV 13 or higher filters can significantly improve PM capture. However, higher-rated filters create more resistance to the HVAC equipment. Before upgrading to MERV-13 or higher, confirm airflow capacity for each air handler to avoid unintended static pressure issues. If system capacity is limited, focus upgrades in building zones with the highest occupancy or where contaminant spikes are most frequent.
Add portable air purifiers: True HEPA air purifiers placed in conference rooms, break rooms, or other high-traffic areas provide localized contaminant removal and greater control during illness outbreak periods or seasonal virus surges. Select units that are properly sized for room volume and have been tested for virus capture. Additionally, look for models with activated carbon to address odours and VOCs.
Building long-term IAQ resilience
While immediate interventions can successfully address short-term winter IAQ challenges, the best results come from long-term strategies that provide lasting protection and operational efficiency. Today’s advanced Air Quality Management (AQM) systems combine real-time air monitoring with automated response, integrating seamlessly and working in concert with the building management system (BMS), HVAC, and ventilation systems.
Modern AQM solutions continuously monitor contaminants like PM, VOCs, and CO2 through the use of IAQ sensors. When levels exceed target ranges, the system automatically adjusts connected purification units, ventilation, and humidity levels to maintain optimal indoor air conditions. Unlike manual adjustments, these systems respond instantly, keeping IAQ consistently within target ranges while minimizing energy consumption. Over time, they can generate significant savings by improving energy efficiency and reducing wear and tear on HVAC equipment. And because AQM systems are scalable, facility managers can initially prioritize high-traffic or problem areas and expand coverage as building needs evolve.
Continuous monitoring also provides actionable data that facility teams can use to identify concerning trends, track seasonal patterns, and prioritize upgrades or maintenance based on evidence, rather than assumptions. An added bonus, the installation of AQM systems can contribute to building certifications such as WELL, LEED and Fitwel, helping facilities demonstrate a commitment to occupant health, wellness, and sustainable building operations.
Facility teams can take immediate, simple steps to improve winter IAQ — from adjusting humidity to upgrading filters and adding purifiers. Without monitoring, however, it’s difficult to know how effective these measures really are. Installing IAQ sensors provides a clear picture of conditions and allows teams to see how changes in ventilation, filtration, or occupancy affect air quality.
For those organizations seeking consistent, high-quality IAQ, advanced AQM systems are a worthwhile investment. With the option to share IAQ data on public dashboards, these systems reassure occupants that their health, wellness, and comfort are a priority while the long-term cost savings they generate are hard to ignore.
Tanner Wozniak is an HVAC Channel Sales Manager at Fellowes Air Quality Management, where he works with and trains HVAC manufacturer representatives throughout the United States.
