The Importance of Indoor Air Quality During Colder Months
As the temperatures drop and the coats come out, most commercial buildings across the UK do what any sensible person would do, which is seal up the windows, turn up the heating, and settle in for the long winter ahead with a hot chocolate in mind. It’s cosy, sure, but there’s one problem, when air stop flowing, indoor air quality (IAQ) often takes a hit.
During the colder months, we spend even more time indoors, staff, customers, students, and visitors alike, and without proper ventilation and HVAC care, airborne contaminants, excess moisture, and poor air circulation can start to affect not just comfort, but health and productivity too, and while it’s easy to focus on keeping warm, the unseen side of HVAC performance (air quality) deserves just as much attention.
Why Indoor Air Quality Drops in Winter
When buildings are sealed tight to keep heat in, it limits the flow of outdoor air that helps dilute and remove pollutants. Everyday indoor activities, cleaning products, office equipment and cooking in the kitchen or canteens all release particles and volatile compounds, and without sufficient ventilation, these pollutants linger in the air.
Combine that with heating systems running at full capacity, dry air from radiators, and less frequent filter changes, and you’ve got a recipe for stale, uncomfortable, and sometimes unhealthy air. Cold weather also means humidity levels tend to plummet, and when the air becomes too dry, it can irritate the skin and throat, and even affect how efficiently heating systems run. On the other hand, too much humidity can encourage condensation and mould, a serious concern especially in schools and older commercial buildings.
The Real Impact on People and Productivity
Poor air quality isn’t just about comfort, it’s about performance, and studies consistently show that indoor environments with proper ventilation and filtration see higher concentration levels, fewer sick days, and improved wellbeing.
For schools, that means students can focus better in lessons and teachers spend fewer days battling winter colds. For offices and commercial sites, it means employees feel more alert, customers feel more comfortable, and the business avoids productivity dips that often hit during the colder months.
If your staff are constantly reaching for the tissues, complaining of headaches, or mentioning “that stuffy feeling”, it might not just be the winter blues, it could be a sign your air quality needs attention.
The Role of Your HVAC System
Your HVAC system does more than just heat or cool your space, it’s your building’s first line of defence for maintaining healthy air quality. A well-maintained system ensures that air is filtered, circulated, and balanced correctly throughout the building.
Here are a few key areas to focus on as the cold sets in:
Filter Replacements - Dirty filters restrict airflow and trap pollutants, making your system work harder and make air quality worse. Changing them regularly is one of the simplest but most effective steps you can take.
Ventilation Checks - Ensure that air handling units and vents are clean and operating properly. Even in winter, you need fresh air circulation to prevent carbon dioxide build-up and condensation.
Humidity Management - Consider humidifiers or integrated controls to keep humidity levels between 40 - 60%, which is the sweet spot for comfort and health.
Routine Maintenance - Winter is when your system works its hardest, so staying on top of servicing helps prevent mid-season breakdowns and ensures optimal performance.
Lessons from the Field
When we work on projects in schools, to be precise, one of the key focuses wasn’t just heating capacity, it was comfort and air quality, and by upgrading to more efficient boilers, better fan coil units, and improved controls, we helped the school maintain consistent, comfortable temperatures while improving ventilation efficiency. It’s a reminder that heating and air quality go together, and a well-balanced system keeps both people and performance in top condition.
Small Steps, Big Difference
You don’t need to overhaul your entire HVAC setup to make a difference, simple actions like booking a winter service check, monitoring humidity, and ensuring vents aren’t blocked by furniture or decorations (looking at you pumpkins), can have a real impact. Think of winter air quality as a team effort, your HVAC system provides the power, but good maintenance keeps everything running in harmony.
A Breath of Fresh Air for Your Building
As the cold weather continues, take a moment to think about what’s in the air around you. A warm building is great, but a warm and healthy building? That’s the real goal.
If you’d like to learn more about improving your building’s air quality this winter or explore energy-efficient HVAC solutions for your site, our team at William Austin is here to help you breathe a little easier.
Written by: Will Judd
Published 30/10/2025