Common AC Problems and Troubleshooting Tips

December 6, 2025

Common AC Problems and Troubleshooting Tips

When the summer heat settles in, a struggling air conditioner can quickly turn from a minor nuisance into a serious disruption. At U.S. Allied Plumbing, Heating, & Cooling, we’ve helped countless homeowners near Aurora, IL handle their cooling system concerns. Below are the most common AC issues, along with practical troubleshooting tips—and guidance on when it’s best to call in a professional.

Poor or No Cooling

Poor or No CoolingIf your AC is running but the house still isn’t cooling down, several factors could be responsible:

  • Clogged or dirty filters blocking proper airflow
  • Refrigerant leaks or low refrigerant levels reducing cooling capacity
  • Malfunctioning or worn internal components affecting performance
  • Damaged or leaky ductwork causing energy loss and uneven cooling

Most of these issues are best identified during a professional inspection. Prompt service not only restores cooling but also prevents larger, system-wide failures.

Frequent Cycling or System Not Responding

Does your AC keep shutting off and restarting too often—or fail to respond altogether? Possible causes include:

  • Thermostat miscalibration or faults disrupting system signals
  • Electrical or mechanical wear causing failures inside the unit
  • Blocked vents or filters altering airflow and pressure balance

Regular maintenance—such as calibrating the thermostat and clearing airflow blockages—can help restore smooth, consistent performance.

Hand using remote to control white air conditioner, temperature set to 24.

Frozen Coils or Ice Buildup

If you notice ice forming on the coils or refrigerant lines, it’s a red flag. Signs of coil freeze include:

  • Visible frost or ice around the AC unit
  • Weak airflow from vents, even while the system is running
  • Warm air blowing despite the AC being on

What to do:


  • Turn the system off immediately to prevent compressor damage
  • Replace dirty filters to improve airflow
  • Avoid setting the thermostat excessively lower than outdoor temperatures
  • Make sure vents are unblocked and the condensate drain is clear
  • After thawing, restart carefully and monitor


If ice returns, it may signal a refrigerant issue that requires professional repair.

Unusual Noises or Odors

Unfamiliar sounds or smells from your cooling system shouldn’t be ignored:

  • Squealing, banging, or rattling may indicate loose or failing parts
  • Musty or foul odors could stem from mold, debris, or poor drainage
  • Electrical burning smells may point to wiring or motor issues

Addressing these problems quickly helps avoid expensive damage and ensures your system operates safely and reliably.

Why Choose U.S. Allied Plumbing, Heating, & Cooling?

At U.S. Allied Plumbing, Heating, & Cooling, we are committed to providing homeowners near Aurora, IL with reliable solutions for every air conditioning challenge. Our team combines years of experience with advanced diagnostic tools to deliver fast, accurate results, whether you’re dealing with clogged filters, refrigerant leaks, frozen coils, or electrical malfunctions. We believe in honest communication, clear recommendations, and repairs that are designed to last, so you can feel confident in your system’s performance. From routine seasonal maintenance to urgent emergency repairs, we remain dedicated to keeping your home comfortable, your cooling system efficient, and your peace of mind intact all summer long.

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