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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.
Imagine, it's 5 minutes after the midnight countdown New Year's eve and the furnace quits. We called TwinTech fully expecting to leave a message and actually spoke with Greg, one of the owners! We had an immediate repair early the next morning & a new furnace within the week. We have entrusted TwinTech with all our home HVAC service needs for over 6 years. That's why this week with an opportunity to purchase a new BBQ, we called them 1st to see about a gas line install. It's chicken on the grill tonight! They are efficient, reliable, honest, hard working, and -- attentive is an understatement.
Wonderful customer service, starting from the job quote (Dave), to the clean install, to the follow-up. Twintech is a small company which installed my Napoleon furnace, A/C, John Wood tank, and ran the line for my gas dryer. The installation was completed as promised in one day. The work area was kept very clean, and they even took care of my old rental tank. The professionalism and wonderful customer service is second to none. They completed all of my rebate paperwork, and now I'm getting $2000 back! You will not be disappointed if you hire this company for your project.
I was referred to Twintech by a neighbour and was not disappointed. Not only was the customer service excellent their workmanship was second to none. Greg and Grant work extremely clean covering the pathway to the furnace room, labeling the essential parts, left the area spotless and were efficient. They cleaned up the mess left by the previous installers (wiring, improperly installed AC coil, and gaps in venting etc). They also ran through the operation of the new furnace and gave me some maintenance tips. Greg and Grant are professional and all around good guys. I will definitely recommend their service to anyone without hesitation.
Very satisfied with service from Twintech , beginning with all the information provided by Dave , which helped make the decision much easier . Installation was very smooth & done on time as promised & cleanup was well done . Would definitely recommend this company & use them again for any future needs . Well done.
Twintech Heating & Cooling Inc. came in and replaced my 39 year old furnace with a beautiful Napoleon variable high efficiency furnace! Their work was efficient and professional and they were a pleasure to deal with, from sales to installation! I would highly recommend them.
After receiving numerous quotes to replace my old furnace and AC unit (which was 20 years old) I went with Twintech. Dave, in sales, answered questions professionally and promptly and worked diligently in order to secure my business. Installation was scheduled the week after and Greg and Peter showed up, as scheduled, and did a fine job installing both units. The site was left tidy and neat. I would highly recommend Twintech for your furnace and AC work.
I chose TwinTech because they installed my new furnace a few years ago and did a great job. When they installed my new A/C, they replaced all parts -- the copper pipes, the housing on top of the furnace and the wiring. (Apparently, the wiring for my old A/C was insufficient.) Their pricing was competitive. The sales representative came to see me within a few hours of my call. My new A/C was installed a few days later and I couldn't be happier with Twintech's professionalism and work. I would recommend TwinTech to any homeowner.
Had a great experience with this company. Great price and great customer service. You wont be disappointed with twintech. Discussed the job with Greg while he was installing who was extremely informative and obviously enjoys the work he does.
I needed my AC unit relocated due to upcoming landscape work. I reached out to the Twintech team through Homestars. Dave connected with me immediately to discuss the project and various options. We decided the best option was to mount the unit on the wall. Greg was in touch with me the same day as well and we scheduled the work for later that same week. This was a small job so I did not think I would get immediate attention. The Twintech team exceeded my expectations in every respect. They were very knowledgeable and friendly. The team arrived exactly on time on the scheduled day and worked efficiently to get the job done quickly. I would definitely use Twintech again for any Heating and AC projects.
I have used Greg Dainty for over 15 years in 3 different homes, for heating, cooling, pool heaters, appliances and bbq lines. Greg has always been so professional, friendly and the workmanship nothing short of fantastic. Greg has always discussed my options and fixing versus replacing, giving his honest opinion and what works best for me cost effective wise and long term. I have valued his opinion so much and have not trusted my gas needs with anyone since using him. I have also referred him to many of my friends and family and have always been so thankful with how well and quickly he looks after us all. I hold Greg in the highest regard and would recommend him to anyone with complete confidence!
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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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