Improve indoor air quality during St. Louis allergy season with better HVAC filtration, humidity control, and smart home tips to reduce pollen, dust, and mold.
If you live in St. Louis, you already know “allergy season” isn’t just a few weeks. Between spring tree pollen, summer grasses, fall ragweed, and the mold that pops up after humid spells and storms, your home can feel like it’s fighting you.
The good news: you don’t have to choose between fresh air and comfortable air. With a few smart HVAC adjustments (and a couple of simple home habits), you can reduce the stuff that triggers sneezing, itchy eyes, congestion, and that “why am I tired?” feeling—without turning your house into a sealed box.
From the phone to the completion of the job everyone is so polite and informative. I had Giovani as our representative and he was very informative and professional, and knew exactly what the problem was. Thanks so much.
Response from the owner:Thank you for the kind review, Frank! We appreciate you and your business.
Zach did an excellent job! Always courteous and friendly. We would highly recommend calling Thomas Hoffmann HVAC for any heating and cooling needs.
Response from the owner:Thank you, Allan! We're glad to hear that Zach provided excellent service and appreciate your recommendation for Thomas Hoffmann HVAC.
Was able to locate the problem right away and replace a switch and add Freon very nice job by this employee. I will recommend Thomas Hoffman for future references.
I had Nick come out. He was awesome. Very knowledgeable, prompt and helpful. I will definitely recommend Thomas Hoffmann HVAC to others in need of HVAC support.
Response from the owner:Thank you, Jack! We're glad to hear that Nick provided you with excellent service. We appreciate your recommendation and look forward to assisting you and others in the future.
From our initial quote until the new furnace and AC were completed, everything was smooth and efficient. Zachary and Giovanni were excellent on-site, taking time to explain the installation as well as leaving the home clean. Thank you Thomas Hoffmann team
Response from the owner:Thank you! We're glad to hear that the installation process was smooth and efficient. Zachary and Giovanni will be pleased to know their efforts made a positive impact. We appreciate your kind words about the team!
Update 4/6/26: Zach Sperling is such a pleasant and knowledgeable technician that I recommend him highly. Thomas Heating has been a wonderful company to work with in my maintenance plan. If you are looking for a reputable company, look no more.
This company is so responsive that I love them. They respond immediately, and I trust them to tell me what needs to be done. I haven’t been steered wrong yet. They are genuinely nice to work with and honest. I use their maintenance program which I highly recommend.
Response from the owner:Thank you for your kind words, we truly appreciate your trust in us and are glad to hear about your positive experience with our services.
work good but got at least 6 messages from them very annoying
Response from the owner:Thank you for your feedback, Harold. We appreciate your input and understand how too many messages can be frustrating. We'll work on improving that experience for you.
Nick was great! He came right out and was able to solve the problem fairly easily. He communicated well and helped us prevent a future problem as well.
Response from the owner:Thank you for the review, Philip! We are happy to hear you had a pleasant experience working with us.
Response from the owner:Thank you, Pat, for your kind words about Giovanni; we appreciate your feedback and are glad to hear that he made a positive impression.
They have never failed to fix my hvac problems. These folks are top tier.
Response from the owner:Thank you for the wonderful feedback, Greg! We're glad to hear that you've had such positive experiences with our team. Providing timely and effective service is our priority, and we're here whenever you need us. Looking forward to assisting you again!
Giovanni was very professional, helpful, patient and helped me figure out the issue, if it was covered under warranty, and next steps. Great overall experience and much appreciated.
Response from the owner:Thank you, Amy! We're glad to hear that Giovanni provided you with such professional and helpful service. Your appreciation means a lot to us!
Always professional and thorough whenever they service our home. We have used Thomas Hoffmann Air Conditioning & Heating multiple times since we moved into our home and will continue to use them in the future.
Response from the owner:Thank you for the thoughtful review, Joe. We appreciate you and your business!
0 stars if I could. Bought a faulty (not to mention overpriced) surface igniter, called back five minutes later after installing, of course they didn’t stand behind their part. Go to Grainger instead. Same (working) part, half the price.
Response from the owner:Hi there. I am unable to locate your customer profile. Please give our office a call at 314-471-7625 so we can get this figured out for you.
My furnace was not working. A very nice gentleman came out this morning and fixed the problem and now I have much needed heat. He was very professional and courteous. I will definitely be using them again when the need arises.
Response from the owner:Thank you for the positive feedback! We're glad to hear that you were pleased with our prompt and friendly service. We look forward to assisting you again in the future!
I will always call Hoffmans for my air and heat needs. They were out to my daughters house that day and fixed it. It was right before the weekend storm with below zero temps the next day. They saved my daughter and grandbabies. I could never thank them more.
Response from the owner:We are so happy to hear that we could help! Thank you for the kind review.
Snow and drifting snow covered intake and out take vents causing the furnace emergency to shut off furnace. Cleaned off the driftibg/ snow off roof and vents furnace works perfect now. Thank you and great job Nick.
Response from the owner:Thanks for the great review, Scott! We appreciate your support.
5 stars! Nick was here to fix my heater within 2 hours of my call. He explained the problem to me thoroughly and got the job done quickly & professionally. Thank you so much!
Response from the owner:Thank you for the kind review, Jennifer! Glad we could help.
Extremely thorough and educational. They do a wonderful job of explaining everything and making sure I was comfortable knowing how the systems worked in my house!
Response from the owner:Thanks for the great review, Matthew! We appreciate your support.
I noticed a strange noise that I was concerned was linked to my furnace. I called Thomas Hoffman Heating & Cooling and Nick came right out. He was very thorough checking all components. Thankfully all checked out for us this visit. Definitely recommend Thomas Hoffman Heating & Cooling!
Response from the owner:Thank you so much for the kind review, Abby! We appreciate your business and look forward to servicing you in the future.
Thomas Hoffman is a wonderful company to work with. Techs are knowledgeable, personable & efficient.
Response from the owner:Thank you, Christine, for your kind words about our team; we appreciate your feedback and are glad to hear you had a positive experience!
Got a quote over the phone. Everything was explained thoroughly. Dakota, my technician arrived and on time, was very professional and knowledgeable. He didn’t try to upsell or change anything. He did a great job. We can already tell the difference since the ducts and vents were cleaned. Would recommend an use Hoffman again in the future.
Response from the owner:Happy to hear you had a pleasant experience using Thomas Hoffmann!
The technician, Ryan, was knowledgeable and helpful in identifying the issue with our mini split AC unit. They are the second company we called after issues with the first and will be using Hoffmann again.
Response from the owner:We are so happy to hear your experience with Thomas Hoffmann was pleasant. Thank you for your kind review, & we look forward to working with you in the future!
Why St. Louis Allergy Season Hits Indoors so Hard
Most people assume allergies are an outdoor problem. But in reality, your home becomes the collection point:
Pollen rides in on clothes, hair, pets, shoes, and packages
Humidity fuels mold in basements, crawl spaces, and damp ductwork areas
Dust and dander circulate when airflow is weak or filtration is poor
Leaky ductwork can pull in attic insulation dust or musty crawl space air
Dirty coils and blowers can spread contaminants and reduce airflow
Start with the Highest-Impact Fixes (most homes need these)
1) Upgrade your air filter the right way (and change it on schedule)
Your HVAC filter is the first line of defense—but only if it’s the right filter for your system and it’s replaced consistently.
What to do:
Use a high-quality pleated filter (not the cheap fiberglass kind)
Consider MERV 8–11 for many homes
If your system can handle it, MERV 13 can capture smaller particles (including many allergy triggers)
Important caveat: A filter that’s too restrictive for your system can reduce airflow, leading to comfort issues and even equipment strain. If you’re not sure what your system can support, a technician can confirm.
Change frequency (rule of thumb)
Every 1–2 months during heavy allergy season
Every 30 days, if you have pets, a dusty home, ongoing construction nearby, or allergy-sensitive family members
2) Keep your home slightly cleaner where it matters most
You don’t need to deep-clean every week—focus on the places that have the biggest payoff:
Entryway: Keep a doormat outside and inside; consider a “shoes off” zone
Bedroom: Wash bedding weekly in hot water; vacuum with a HEPA-rated vacuum
Floors: Damp mop hard floors (dry sweeping stirs allergens back up)
Pets: Brush pets regularly and wipe them down after outdoor time (especially paws)
3) Control humidity (this is huge in St. Louis)
St. Louis humidity can push indoor moisture higher than you think—especially in basements and older homes. High humidity doesn’t just feel sticky; it can help mold thrive and make dust mites happier.
Target indoor humidity:
Aim for 30–50% (many homes feel best around ~40–45%)
Make sure bath fans and kitchen ventilation actually vent outside
Address water intrusion, sump issues, and damp crawl spaces
HVAC Upgrades Can Make a Big Difference
4) Consider a media filter or high-efficiency filtration upgrade
If your current setup relies on a 1-inch filter, you may benefit from a deeper media filter cabinet (often 4–5 inches). These can:
Capture more particles
Restrict airflow to less than a very “tight” 1-inch filter
Last longer between changes (depending on conditions)
5) Add air purification—only if it matches your goals
“Air purifier” can mean many things. Here’s what tends to be most useful for allergy season:
HEPA filtration (portable or whole-home add-on)
Excellent at capturing fine particles
Great for bedrooms and living spaces
Whole-home options exist, but must be designed correctly to avoid airflow issues
UV systems
Most helpful for microbial control (like mold on coils) rather than pollen
A good option if you’ve had recurring musty odors or visible growth concerns near HVAC components
Bipolar ionization/ionizers
Some homeowners ask about these; effectiveness and best-use cases vary widely by product and installation. If you’re considering one, focus on proven performance data and proper application—not buzzwords.
Schedule a Seasonal HVAC Tune-Up
A tune-up isn’t just about preventing breakdowns. It also helps:
Coils and blower components can collect dust and biofilm
Drain lines can back up and create moisture problems
Airflow and static pressure issues can reduce filtration effectiveness
Small problems (like a weak capacitor or dirty coil) can cause longer run times and poor humidity control
Frequently Asked Questions
Many homes do well with MERV 8–11; some systems can support MERV 13. The “best” filter is one that improves particle capture without restricting airflow. If you want, we can recommend the appropriate rating for your system.
Often every 30–60 days during peak pollen periods. Homes with pets or high dust may need monthly changes.
Sometimes, but it depends on what’s actually in the system. If there’s visible buildup, post-construction dust, or contamination, it may help. In many cases, filtration, sealing leaks, and proper maintenance yield more consistent long-term results.
Yes—by improving filtration and humidity control. A clean, properly functioning AC can reduce indoor moisture (which helps reduce mold and dust mite issues) and keep air moving through the filtration system.
Often, it’s moisture-related: a dirty evaporator coil, a drain issue, or high indoor humidity—sometimes combined with duct leakage that draws in damp air. It’s worth diagnosing early.
Need Help Improving Indoor Air Quality in St. Louis?
If you’re in St. Louis, Kirkwood, Des Peres, or nearby and want a clear plan—filtering, humidity, airflow, and any IAQ upgrades that actually make sense for your home—we can help. Call us at (314) 471-7625 or visit our online contact form.
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At Thomas Hoffmann Air Conditioning & Heating, we pride ourselves on being a locally owned and operated HVAC company. With more than 30 years of experience and a master technician and mechanical engineer as our owner, we can replace, repair, and maintain your business or home’s HVAC system.
