If your air conditioner keeps turning on and off every few minutes, it’s usually a sign that something isn’t working correctly.
This issue is commonly known as AC short cycling, and it can lead to higher energy bills, reduced comfort, and unnecessary wear on your HVAC system.
For homeowners in St. Louis, short cycling is especially frustrating during hot, humid summer days, when your air conditioner should be running steadily to keep your home comfortable.
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.
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work good but got at least 6 messages from them very annoying
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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.
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They have never failed to fix my hvac problems. These folks are top tier.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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!
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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!
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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!
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Thomas Hoffman is a wonderful company to work with. Techs are knowledgeable, personable & efficient.
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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.
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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.
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woke up to a very cold house, called Thomas Hoffmann, they were able to come out a couple of hours later and get the issue resolved. Always trust them, they have always been quick to respond and get either the heating or ac issue fixed that day. Also a great price!!!! give them 10 stars if i could, Thank You JS
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The technician Giovanni was excellent and on time very professional and efficient and knowledgeable of the project at hand ,gave great advice but most of all did great work 👏 thank you .
Response from the owner:We are so happy to hear you had a great experience, Sam! Thank you for the review, and thank you for your business.
What is Air Conditioner Short Cycling?
Short cycling happens when your air conditioner:
Turns on
Runs briefly
Shuts off quickly
Then turns back on again shortly after
Instead of completing a full cooling cycle, the system repeatedly starts and stops. Normally, an air conditioner should run for 10–15 minutes per cycle, or longer, depending on outdoor temperatures and cooling demand. When cycles become extremely short, the system never fully cools your home or properly removes humidity.
Why Short Cycling Is a Problem
When your AC keeps turning on and off, it can cause several issues:
One of the most common causes of AC problems is a clogged air filter. When the filter becomes dirty, airflow through the system is restricted. This can cause the evaporator coil to become too cold, disrupting normal operation. Symptoms may include:
AC turning off quickly
Reduced airflow from vents
Ice forming on the indoor coil
Changing the air filter every 1–3 months can help prevent this problem.
If your AC coil freezes, the system may begin short-cycling. Frozen coils often occur due to:
Dirty air filters
Blocked vents
Low refrigerant levels
Poor airflow
When the coil freezes, the AC may shut down to prevent damage. If you notice ice on refrigerant lines or the indoor unit, it’s time to schedule AC repair.
Many homeowners are surprised to learn that an oversized AC can cause short cycling. A system that is too large cools the home too quickly and shuts off before completing a full cycle. This leads to:
Frequent on-and-off cycles
Poor humidity removal
Uneven temperatures
Oversized systems are sometimes installed when proper load calculations are skipped.
Electrical components help regulate when your AC starts and stops. If these components begin to fail, the system may cycle erratically. Possible electrical issues include:
Failing capacitors
Loose wiring connections
Control board problems
Contactor issues
Electrical repairs should always be handled by a licensed HVAC technician.
5. Blocked or Closed Vents
Your HVAC system relies on balanced airflow throughout your home. If too many vents are closed or blocked, pressure builds up in the duct system and can interfere with proper system operation. This can cause:
Short cycling
Reduced airflow
Uneven cooling
Make sure supply vents and return vents remain open and unobstructed.
Signs You Should Call for Air Conditioner Repair
Short cycling should never be ignored. You should schedule AC repair if:
Addressing the issue early can prevent more expensive repairs later.
How Regular AC Maintenance Prevents Short Cycling
Many causes of short cycling can be prevented with regular HVAC maintenance. A professional AC tune-up typically includes:
Checking refrigerant levels
Cleaning condenser coils
Inspecting electrical components
Checking airflow
Testing thermostat operation
Inspecting the evaporator coil
Regular maintenance helps your system run efficiently and reliably during the St. Louis summer.
Air Conditioning Repair in St. Louis
If your air conditioner keeps turning on and off, a professional inspection can identify the cause and restore proper operation. Thomas Hoffmann Air Conditioning & Heating LLC provides trusted AC repair services for homeowners throughout the St. Louis metro area. Call today to schedule AC repair:(314) 471-7625
24/7 Service Call Now
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.
