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Winter Allergies and Your HVAC System

When people think of allergies, spring pollen usually comes to mind.
But for many homeowners, allergy symptoms actually get worse during winter.
If you’re sneezing, coughing, or dealing with dry, irritated sinuses when the heat is on, your HVAC system may be playing a role.
Understanding how winter allergies work—and how your heating system affects indoor air quality—can help you breathe easier all season long.
Why Allergies Can Be Worse in Winter
During winter, homes are sealed tightly to keep cold air out.
While this improves energy efficiency, it also traps allergens indoors.
Unlike seasonal outdoor allergens, winter allergies are usually caused by indoor irritants.
Common winter allergy triggers include:
Dust and dust mites
Pet dander
Mold spores
Dry air irritation
Indoor air pollutants
Because your HVAC system constantly circulates air, it can either reduce these allergens—or spread them throughout your home.
How Your HVAC System Affects Winter Allergies
Your heating system is responsible for moving air through your home.
If it isn’t properly maintained, it can worsen allergy symptoms instead of improving comfort.
Air Circulation and Allergen Spread
Forced-air heating systems circulate air through ductwork and vents.
When dust, dander, or mold builds up inside the system, those particles get redistributed every time the heat runs.
Dirty Filters and Poor Filtration
Clogged or low-quality air filters allow allergens to pass through easily.
Over time, this leads to higher concentrations of airborne particles and increased allergy symptoms.
Dry Indoor Air
Heating systems reduce indoor humidity, which can:
Dry out nasal passages and sinuses
Make allergy symptoms feel more severe
Increase irritation of the throat and eyes
Dry air doesn’t cause allergies, but it can make existing symptoms much worse.
The Role of HVAC Filters in Allergy Control
Your HVAC filter is one of the most important tools for managing winter allergies.
High-quality filters can:
Trap dust, pollen, and pet dander
Reduce airborne allergen levels
Improve overall indoor air quality
For allergy-prone households, filters with higher MERV ratings are often recommended.
However, these filters must be changed regularly to prevent airflow restriction and system strain.
Most homes should replace filters every 1 to 3 months during winter, depending on usage and indoor conditions.
Ductwork and Hidden Allergens
Even with a good filter, allergens can accumulate in ductwork over time.
Duct-related allergy problems may come from:
Dust buildup
Mold growth caused by moisture
Air leaks pulling contaminants from attics or crawl spaces
Old or damaged insulation inside ducts
Sealing and cleaning ductwork can significantly reduce the amount of allergens circulating through your home.
Mold Growth and Heating Systems
Mold is a major indoor allergen and can be especially problematic in winter.
Condensation, humid basements, or neglected HVAC components can create the perfect environment for mold growth.
Signs mold may be affecting your air quality include:
Musty or earthy odors when heat runs
Persistent allergy symptoms indoors
Visible mold near vents or HVAC equipment
Professional HVAC inspections can identify moisture issues and prevent mold from spreading through your system.
How to Reduce Winter Allergies With Your HVAC System
If winter allergies are affecting your comfort, your HVAC system can be part of the solution.
Steps homeowners can take:
Replace air filters regularly
Schedule annual heating system maintenance
Keep vents and returns clean and unobstructed
Use a whole-home humidifier to balance moisture
Seal duct leaks to prevent contaminant entry
Consider air purification or UV systems
These improvements help create cleaner air while improving heating performance and efficiency.
When to Call an HVAC Professional
If allergy symptoms persist despite basic maintenance, it’s time to bring in a professional.
You should schedule an HVAC inspection if you notice:
Excessive dust buildup
Uneven heating or weak airflow
Strange odors when the system runs
Worsening allergy symptoms indoors
An HVAC professional can identify airflow issues, filtration problems, or hidden contaminants affecting your indoor air quality.
Final Thoughts
Winter allergies are often an indoor air quality issue—and your HVAC system plays a major role.
With proper filtration, humidity control, and regular maintenance, your heating system can help reduce allergens instead of spreading them.
At Twintech Heating & Cooling, we help homeowners improve comfort and air quality during the winter months.
If you’re struggling with allergies while running your heating system, professional HVAC solutions can make a noticeable difference in how you feel at home.
Great service and great people to deal with, from sales to installer. I highly recommend this company.
Twintech replaced our aging furnace and air conditioner recently. I highly recommend this company. Their quote was competitive, they were on time and respectful of our home and extremely professional. From the salesman to the installers and the owner who followed up afterward to ensure we were satisfied, we are very pleased with the service. We are looking forward to working with this company for all of our HVAC needs for the years to come. Excellent workmanship and service!
We wanted to get our AC replaced as it was 22-years old and added to this our furnace was costing more and more to repair. So, we decided to get both the furnace and AC replaced.
After going through a few quotes and product reviews we decided to go with Twintech. The three-men crew arrived early in the morning, wasted no time and got to work right away. By 2:00 pm, they were all done. Ive found their work to be top notch and they were completely professional. I had all my questions answered to my satisfaction both during the progress of their work and at end.
I have pleasure in recommending Twintech to anyone who is looking to get their furnace or Ac replaced
Nathan S.
Our air conditioner died On a Saturday and within hours Dave came out to take a look and discuss replacement/repair options.
The new air conditioner was installed on the Wednesday. The new unit was installed quickly. The installers were friendly and cleaned up afterwards.
We noticed a slight leak around the furnace that night and they came out the next day and fixed the issue. It has been working great and is quieter than our previous unit.
Very satisfied and would highly recommend TwinTech.
I contacted TwinTech to replace my 20-year old A/C. Dave, their service rep, promptly replied and was at my home within 2 hours. He was friendly and knowledgeable and didn't try to upgrade or oversell their A/C units but suggested the best fit for my small 1000 feet bungalow. Although this was during a heatwave and very busy, they were able to fit me in 2 days later. The TwinTech crew installed a 1.5 ton Ducane A/C unit that is now running smoothly while maintaining a constant cooling temperature. The crew were very courteous, professional and efficient and I will definitely recommend TwinTech to family and friends. I much appreciated your great service.
Nancy M., Oshawa
We had a great experience. The guys who installed our a/c did a nice job. Cleaned up.
excellent crew, fast and efficient! Would call them again when I need a new furnace.
Professional, courteous and efficient, dont need to say more than that! Use them you will not regret it.
TwinTech was a pleasure to deal with from the estimate through installation. We replaced a 28 year old a/c unit with one recommended by TwinTech's sales representative Dave who took the time to go over the product with us and answer any questions. The warranty is for 10 years parts and labour and they will complete the registration for you. Installation was by Greg (owner) and Mitch and Spencer who were quick and efficient and left everything clean and tidy.
Very professional, from the sales consultation and inspection to the final installation. Met every expectations we had for the job. A local business with great client support. We highly recommend. Twintech is a blue chip! Thanks!
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We are very happy to recommend this company to everyone. Our furnace broke down on Sunday morning. We phoned them and before noon Grant the owner showed up. He worked on the furnace for about a hour not wanting to give up to fix the problem. The furnace was 17 years old. I was the one talking about replacing it. End result was the next day it was all done. On the Sunday Bob came over with heaters to warm up the house. We decided to replace the water heater at the same time. Thanks Grant for the excellent work. Thumbs up.
Right on time. Explained how to work the HRV in a different way so the house would not be so dry. Changed my whole house water filter for me as well. Friendly, helpful, caring service!
Very pleased with the professional service that TwinTech Heating and Cooling provided in replacing my furnace. I got several quotes from different service providers. Their price was excellent and they explained the features very well. We are very glad we went with TwinTech and highly recommend their services.
We were new homeowners in need of a second opinion. TwinTech Heating & Cooling were Amazing and professional. Very knowledgeable and great service all around. Recommend to anyone looking for honest and reliable services. Treated with respect and care. Thank you Greg, Mitch and Bob!
TwinTech is an excellent and honest company! I called them for a second opinion after being told by another company that I needed to replace my furnace. Turns out this was not the case at all! I did not need a new furnace. TwinTech did not push to make an unnecessary sale and saved me from a huge expense. Bob and Mitch were extremely professional and above all honest! I definitely recommend TwinTech!
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