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What Should I Do If My Air Conditioner Is Running but Not Cooling?

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If you notice that your air conditioner is running but has stopped cooling the air, you should start investigating the possible causes.

Person checking warm airflow from floor vent in home, diagnosing AC running but not cooling issue

Having an HVAC malfunction during the summer can be really uncomfortable. If you notice that your air conditioner is running but has stopped cooling the air, you should start investigating the possible causes. This symptom can be attributed to a list of issues that may or may not require professional attention. 

Here is what to start looking for and what to do when your unit stops cooling. 

James H.
2 hours ago
Came out immediately after a time slot opened and fixed the AC issue.
Response from the owner:Thank you, James, for your kind words! We're glad we could address your AC issue promptly.
Margaret F.
2 days ago
Excellent service from Nick! Friendly was super knowledgeable!
Response from the owner:Thank you, Margaret! We appreciate your kind words and will make sure to pass along your praise to Nick for his excellent service.
Teresa F.
6 days ago
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.
Marilyn H.
1 week ago
Nick was was great! He provided great service, explained everything, and was patient and kind.I definitely recommend using Hoffman!
Response from the owner:Thank you, Marilyn! We're glad to hear that Nick provided you with excellent service and made your experience enjoyable. We appreciate your recommendation!
Jasmine W.
2 weeks ago
The whole team was great, professional and friendly. Scheduling was easy and well organized, they had many options for different price points and financing options. Thank you!
Response from the owner:Thank you for the thoughtful review, Jasmine! We appreciate your support and continued business.
Henry D.
2 weeks ago
I have complete trust in Thomas Hoffman AC . I have had multiple
technicians who are always polite and knowledgeable.
Response from the owner:Thank you for your trust in our team, Henry! We appreciate your kind words about our technicians.
Theresa S.
2 weeks ago
Love that it’s the same technician every time. Let’s me know what he found and any concerns he might have regarding our units. Great customer service.
Response from the owner:Thank you, Theresa! We're glad to hear you appreciate having the same technician and the communication about your units. Your feedback on our customer service means a lot to us!
Frank P.
2 weeks ago
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.
Allan G.
2 weeks ago
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.
William W.
2 weeks ago
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.
Response from the owner:Thank you, William! We're glad to hear that our team was able to quickly address the issue and that you had a positive experience with Thomas. Your recommendation means a lot to us!
Jack D.
3 weeks ago
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.
FFE L.
3 weeks ago
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!
Bob De P.
3 weeks ago
Courteous friendly and efficient! What else could you want!
Response from the owner:Thank you, Bob! We're glad you found our service courteous, friendly, and efficient – that's exactly what we strive for!
Princess C.
3 weeks ago
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.
Julie N.
3 weeks ago
So helpful! Straight into the point with no runaround or Negotiating up sells! Quick and efficient!
Response from the owner:Thank you for the great review, Julie! We appreciate your business and the support!
George G.
4 weeks ago
Great fast courteous service, knowledgeable.
Response from the owner:Thank you for recognizing our fast and courteous service, we appreciate your feedback!
harold B.
4 weeks ago
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.
Philip D.
1 month ago
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.
Pat Keith T.
1 month ago
Geovanni is great!
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.
Greg D.
1 month ago
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!
Amy K.
1 month ago
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!
Joe G.
1 month ago
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!
Daniel D.
1 month ago
Met Nick at ACCA - conference for HVAC contractors. He’s an expert! 100%
14 years in the business, doing a great job and service.
Response from the owner:Hi Daniel! So happy to hear you enjoyed Nick's company. We are lucky to have him.
Kelly R.
2 months ago
Very easy to work with. Technician kept me informed about what was going on through the whole process.
Response from the owner:Thank you for the great review, Kelly! We appreciate your business.
Jordan P.
2 months ago
Nick was awesome! He was extremely professional and answered any questions I had. Would highly recommend!
Response from the owner:Thank you for your kind review, Jordan! We are happy to hear you had a great experience using Thomas Hoffmann.
Jill P.
2 months ago
Got the job done fast and explained every step as it was happening!
Response from the owner:We are happy to hear you had a great experience! Thank you for the kind review.
Veronica V.
2 months ago
We have a tankless water heater that needed cleaning and a new part, they came out very quickly and got the hot water back again. Thank you!
Response from the owner:We are happy to hear you had a pleasant experience! Thank you for the kind review, and your continued support.
jay70001
3 months ago
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.
Katherine T.
3 months ago
Always a great experience. Was able to get out same day to help, knowledgeable of old homes, including their systems and new systems as well.
Response from the owner:Thank you for your kind review, Katherine! We appreciate your business.
April T.
3 months ago
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!
Kathleen D.
3 months ago
Ryan was very professional, knowledgeable, and thorough. I was able to get an appointment the same day during a biter, snowy day.
Response from the owner:We are so glad to hear you had a pleasant experience, Kathleen!
Melinda D.
3 months ago
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.
Scott S.
3 months ago
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.
Jessica B.
3 months ago
Came during a storm with emergency call for heat- did a quick and fast job getting furnace running! Whoot!
Response from the owner:Thank you for the great review, Jessica! We appreciate your support.
Jennifer H.
3 months ago
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.
Matthew B.
3 months ago
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.
Joe C.
3 months ago
Nick did an amazing job, on time, very knowledge and professional.
Response from the owner:Thank you for the great review, Joe. We look forward to servicing you in the future!
anna M.
3 months ago
installed humidifier and hepa filter. Very pleased with service.
Response from the owner:We are happy to hear that you had a pleasant experience!

Create the Proper Conditions for a Diagnosis

Before you can identify the possible causes of your HVAC malfunction, make sure you create good conditions for testing it. 

  • First of all, close all your windows to prevent hot air from coming inside. 
  • Check the current room temperature and set your thermostat to a cooler value, it may simply not be set correctly.
  • If you are using other air processing appliances like humidifiers or air purifiers, turn them off.
  • Check the vents and make sure they are not obstructed.

Once you have created these conditions, it’s time to find the culprit through elimination. It’s possible that after taking these steps, you may notice that your system is actually working correctly. If not, here is a list of the most common causes for an HVAC unit that is running but not cooling. Get in touch with an HVAC technician who can help identify and resolve any issues with your air conditioner.

Refrigerant Leaks

Refrigerant is the substance used in air conditioning units and refrigerators to cool the air or fluid that circulates through them. If your HVAC system has refrigerant leaks, it will simply not be able to cool the air, but it will still circulate it. Some units can self-diagnose low refrigerant, but without such a feature, only an HVAC professional can measure the level of the refrigerant. 

Clogged HVAC Interior

Air not cooling can be a sign of improper maintenance of the HVAC unit. Follow the manufacturer’s instructions for routine maintenance and clean the air filters, coil, condenser, evaporator, etc. Clear any debris or vegetation around the outdoor unit and make sure the unit is not flooded with water. 

Insufficient Airflow

Another cause for the HVAC not cooling down your house is that the cool air never gets to the interior. Fortunately, this means that the unit itself works perfectly, but you need to investigate the airflow before the problem worsens. Check the cold air returns to see if there is any suction (try using a paper tissue to check the movement of the air). All the vents in your house should let the air flow properly.

Thermostat Malfunction

Your HVAC unit may be working perfectly, but the thermostat is having some sort of issue. Make sure it works properly by checking the display if it’s blank you might want to try replacing the batteries or calling an HVAC expert to check the wiring. 

Electrical Malfunction

Most issues that HVAC repair teams deal with are caused by electrical malfunctions. If you notice that your HVAC unit has stopped cooling the air, check the electric panel to see if any of the breakers were tripped. They should be labeled for easy identification. Try flipping them in the off position and see if that solves your problem.

Frequently Asked Questions

This could be due to a variety of issues such as low refrigerant levels, clogged filters, or electrical problems. It’s best to have a professional HVAC technician diagnose and resolve these issues, as they have the tools and expertise to handle refrigerants and electrical systems safely.

Often, this indicates that something is preventing the system from functioning efficiently. Possible reasons include a malfunctioning thermostat, blocked vents, or internal obstructions. A professional can conduct a thorough check to identify and fix the underlying problem.

It’s advisable to ensure that the thermostat is set correctly and that there are no obvious blockages affecting air flow. Beyond these basic checks, contacting a qualified HVAC professional is the safest way to handle issues like refrigerant leaks or system recalibration.

Handling HVAC issues involves dealing with complex components that might require handling hazardous materials or electrical systems. Therefore, while routine maintenance like cleaning accessible filters and ensuring clear surroundings can generally be done safely, any deeper issues should be addressed by professionals.

Common reasons can include issues with the thermostat settings, blockages in the air circulation paths, or mechanical failures within the unit. An HVAC technician can offer the best solutions after a professional assessment, ensuring that any repairs or adjustments are done safely and effectively.

If you notice that your air conditioner is running but not cooling your home, give our team a call today and we’ll get to the bottom of your issue!

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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.

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