Don’t let something as simple as a dirty air filter reduce your comfort or drive up your bills. Call us today to keep your HVAC system clean.
Changing the air filter is one of the simplest yet most important maintenance tasks for your home’s HVAC system. But despite how easy it is, it’s also one of the most commonly overlooked. A dirty air filter doesn’t just affect your air quality—it can lead to higher energy bills, poor performance, and costly repairs.
If you’re a homeowner in St. Louis or surrounding areas like Ballwin, Kirkwood, or O’Fallon, this guide will help you spot the warning signs of a dirty filter and show you how to fix the problem fast.
Thomas Hoffman was very responsive to our after hours inquiry, even walked us through some trouble shooting over the phone. We provided pictures of the unit and they were able to quickly buy, schedule and install the part to keep our family warm!
Response from the owner:Thank you, Ali! We're glad to hear that Thomas was responsive and helpful in getting everything sorted out for you and your family. Your feedback means a lot to us!
Nick came by, identified the problem quickly and had it fixed. Great service!
Response from the owner:Thank you, Ted! We're glad to hear that Nick provided you with quick and effective service. Your feedback is greatly appreciated!
Great service. Responsive. Well trained technicians. Honest friendly and thorough. I highly recommend Tom Hoffmann and his team.
Response from the owner:Thank you for your kind words! We appreciate your recommendation and are delighted to hear about your positive experience with our team.
Ryan Taylor with Thomas Hoffman did an outstanding job in servicing our unit & explaining everything to me, especially how our humidifier worked, since we were new home owners & had not had one before. Thank you!
Response from the owner:Thank you! We're glad to hear that Ryan and Thomas provided you with excellent service and helped you understand your new humidifier. We appreciate your feedback!
Response from the owner:Thank you, Hank, for your wonderful feedback; we're glad you enjoyed the fast, friendly, and professional service, and we'll be sure to keep up the great work!
As always, the Hoffmann technician Zach was polite, professional, and efficient. Pricing is reasonable and even more importantly, they are dependable. I will continue to use Thomas Hoffman A/C and Heating.
Response from the owner:Thank you, Mark, for your kind words about our technician and for your continued trust in Thomas Hoffman A/C and Heating; we truly appreciate your support!
Response from the owner:Thank you, Brandon! We appreciate your kind words and are glad to hear about your positive experience with Hoffmann’s professionalism and thoroughness.
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.
Our service technician arrived right on time and was professional, friendly, efficient and courteous. We couldn’t ask for more.
Response from the owner:Thank you for sharing your positive experience with our service technician! We appreciate your kind words and are glad to hear that you were satisfied with the service provided.
I'm a new customer and had my first appointment for furnace check.My tech was Zack and what a professional. He explained how he checked system and answered all my questions. This was a very good experience
Response from the owner:Thank you, Patricia, for your kind words! We're glad to hear that Zack provided you with a professional and informative experience during your furnace check. Your satisfaction means a lot to us!
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!
I called on December 25th at midnight and started leaving a message and Thomas Hoffman the owner called me back almost immediately. He said he would come out the next morning between 8:00 and 10:00 am snd he was promptly on time. He fixed my problem and while he was there I decided to get an estimate for a new furnace and air conditioning unit. The price was very reasonable and the installers one of them being his son were both very professional very courteous, polite, arrived on time and finished the same day. I enjoy knowing that I now have the support of Thomas Hoffman heating and air conditioning along with the peace of mind that comes with owning a Trane. Nothing stops a Trane.
Albert Koesterer
Response from the owner:Albert thanks so much for your kind reviews and your business. We truly appreciate it!!!
The Thomas Hoffmann team did a great job taking care of our semi annual HVAC maintenance. They not only worked with us to schedule the visit, but also did an excellent job sending us reminders on when they would be out.
Response from the owner:Thank you so much for the great review, Bob! We appreciate your support and are happy to hear you had a great experience!
Nick was excellent. Super profession, quick, and up front with the pricing (which was fair). Hopefully we don't need to call anyone to fix our AC again, but if we do - I'm calling Nick!
Response from the owner:Thank you, Layton, for your amazing review! We really appreciate your support and hope to be your first call for any future repairs!
Same day service. Technician arrived as scheduled. Replaced capacitor quickly. Friendly technician. Repair cost $429 seemed high for inexpensive part and 20 minutes labor.
Response from the owner:Thank you, Tom, for your feedback! We're glad to hear the technician was prompt and friendly, though we understand your concerns about the repair cost. We appreciate your insights and hope to serve you again in the future.
Response from the owner:Thank you so much, Al, for your excellent review; we truly appreciate your support and are glad to hear you had a great experience!
Thomas Hoffmann is the most professional and courteous of all the HVAC companies in St. Louis. It has kept my HVAC systems in good working order through the hottest and coldest days for many years.
Response from the owner:Thank you, Jonathan, for your kind words about our professionalism and courtesy; we truly appreciate your support!
I notified two companies at the same time regarding a malfunctioning AC unit and Wow! Super fast response from Hoffmann on a weekend no less, to fix our AC unit. Hoffmann’s tech responded to my call immediately and fixed our AC before Galmiche has even responded. Used to be a Galmiche customer, but will use Thomas Hoffmann from here on out!
Response from the owner:Thank you, Darlene, for your fantastic feedback! We're glad to hear that our team was able to respond quickly and resolve your AC issue. We appreciate your trust in us moving forward!
Ryan did a great job with my AC reinstall. Very knowledgeable company with Tom Hoffmann providing the engineering expertise.
Response from the owner:Thank you, Steve! We're glad to hear that Ryan did a great job on your AC reinstall, and we appreciate the shoutout to Tom's expertise. Your satisfaction means a lot to us!
These guy's are amazing same day service very well priced for the knowledge they have ask before doing anything to confirm they're my new go to
Response from the owner:Thank you, Cory! We're glad you found our service amazing and appreciate your kind words about our pricing and knowledge. We're here for you anytime!
My ac compressor was replaced. They always do a good job and they are always available when you need them.I think the price was a little too high since they only had to change the compressor in my unit. The compressor was under the warranty. Other than that Im very satisfied with the job the technician did.
Response from the owner:Thank you, Carlos, for your feedback and for recognizing the hard work of our technician; we appreciate your satisfaction with the job done and will take your pricing comments into consideration.
I was very pleased with your service. Prompt response would was most appreciated. The technician was very knowledgeable and prepared for the work. Also he was very personable and professional.
Response from the owner:Thank you, Richard, for your kind words; we appreciate your recognition of our technician's knowledge and professionalism, and we're glad you had a positive experience with our service.
Thank goodness for them coming out so quickly. Got our whole job done and we are COOL again. Thanks so much!!!
Response from the owner:Thank you, Sandy! We're so glad to hear everything got done quickly and you’re feeling cool again. We appreciate your kind words!
Had an amazing experience with Thomas Hoffman. They were very professional and solved the problem quickly. I would highly recommend!
Response from the owner:Thank you, Alex, for your wonderful feedback! We're glad to hear that Thomas was able to assist you so effectively. Your recommendation means a lot to us!
Zac did our service today. A very professional and courteous young man. He did a thorough inspection and cleaning on our HVAC system.
Response from the owner:Thank you, Tom, for your kind words about Zac's professionalism and thoroughness during your HVAC service; we appreciate your feedback!
Why Air Filters Matter
Your HVAC filter is the first line of defense for your heating and cooling system. It traps:
When the filter becomes clogged, it restricts airflow and causes your system to work harder, leading to a chain reaction of problems—from decreased indoor air quality to system breakdowns.
Top Warning Signs of a Dirty Air Filter
1. Reduced Airflow
If your system seems to be blowing less air than usual, a clogged filter may be the culprit. Reduced airflow indicates that your HVAC struggles to circulate air through the dirty filter.
2. Hot or Cold Spots in the Home
Uneven temperatures between rooms often indicate that the HVAC system isn’t circulating air efficiently, frequently due to filter blockage.
3. Unexplained Increase in Energy Bills
Dirty filters force your system to run longer to reach the desired temperature. Over time, this leads to increased energy usage and higher utility bills, especially during St. Louis’s hot summers and frigid winters.
4. More Dust Around the House
Are you dusting more than usual? A clogged air filter can’t effectively trap particles, allowing dust to circulate and settle on your furniture and floors.
5. Musty or Stale Odors
When the filter is dirty, moisture and debris can create a breeding ground for bacteria or mold, leading to unpleasant smells whenever the system is on.
6. Frequent HVAC Cycling
Short cycling—when your system turns on and off frequently—can indicate that restricted airflow affects your system’s ability to maintain consistent temperatures.
7. System Overheating or Freezing Up
In extreme cases, restricted airflow can cause your furnace to overheat or your AC coils to freeze, leading to costly repairs or even full system shutdowns.
How Often Should You Replace Your Air Filter?
There’s no one-size-fits-all answer, but here are general guidelines for St. Louis homeowners:
Home Type or Condition
Filter Replacement Frequency
Standard home, no pets
Every 90 days
One pet
Every 60 days
Multiple pets or allergies
Every 30–45 days
Smoking indoors
Every 30 days
High allergy season (spring/fall in STL)
Every 30–45 days
How to Check If Your Filter Is Dirty
Turn off your HVAC system for safety.
Locate and remove the filter (usually behind a return vent or inside the furnace).
Hold it up to a light source. If you can’t see light through it, it’s time to replace it.
The Long-Term Costs of Ignoring a Dirty Filter
Neglecting your air filter may seem minor, but it can lead to:
Reduced system lifespan
More frequent breakdowns
Poor indoor air quality
Increased energy bills
More allergens and contaminants in the home
Need Help Changing Your Filter or Improving Air Quality?
Don’t let something as simple as a dirty air filter reduce your comfort or drive up your bills. Whether you’re due for seasonal maintenance or need help picking the right filter, Thomas Hoffmann Air Conditioning & Heating is here to help.
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.
