Why Is My Air Conditioner Running but Not Cooling
Air Conditioning Insights for Savannah Homeowners
When your air conditioner is running but not cooling, especially in Savannah’s hot, humid climate, it’s both frustrating and potentially costly. Before calling an HVAC professional, here are the most common causes and what you can do.
1. Thermostat Settings or Malfunction
Begin with the thermostat. Ensure it’s set to “cool” and that the fan setting is at “auto,” not “on.” When set to “on,” the fan may circulate air even when the compressor isn’t engaging, resulting in airflow without actual cooling.
If settings are correct but temperatures are off, batteries may be low or the thermostat itself may be faulty. A misreading thermostat can prevent proper cooling cycles.
2. Dirty Air Filters
Clogged or dirty filters restrict airflow, reducing cooling capacity and forcing the system to work harder. This can lead to increased power usage, uneven cooling, or even frozen evaporator coils.
In Savannah’s high pollen and dust environment, filters should be checked every month and replaced every 1–3 months depending on use.
3. Blocked or Dirty Condenser Coils
Your outdoor condenser unit must release heat efficiently. Leaves, grass clippings, dirt, or vegetation can block airflow across the condenser coils. If the coils are dirty or obstructed, the system can’t expel heat properly, so indoor air remains warm despite the AC running.
Maintain at least a two-foot clearance around the unit and gently rinse or brush clean the coils regularly.
4. Low Refrigerant or Refrigerant Leak
Refrigerant is essential for heat transfer. If levels drop—usually due to leaks—the system runs but fails to cool. Signs might include a hissing sound near refrigerant lines or ice buildup on coils or pipes.
Handling refrigerant requires a licensed technician to locate leaks, repair them, and recharge the system.
5. Frozen Evaporator Coil
An evaporator coil may freeze when airflow is restricted (from a dirty filter or blocked returns) or refrigerant levels are low. When this happens, the coil can’t cool properly and air won’t circulate effectively. Shut the system off and allow it to thaw naturally—usually several hours—and then address the underlying issue.
6. Electrical Issues and Failing Capacitors
A malfunctioning capacitor or electrical component can prevent the fan or compressor from starting correctly. You might hear buzzing, notice the outside unit isn’t engaging, or see frequent tripped breakers.
Capacitors typically fail in units older than about 5 years and should be diagnosed and replaced by a qualified HVAC technician.
7. HVAC System Size or Age
An AC system that is too small may run continuously but still fail to reach the desired temperature. This is common in older homes or after home additions, especially in hot climates like Savannah.
Similarly, units more than 10‑15 years old may be nearing the end of their lifespan. In such cases, performing repairs on aging equipment isn’t always cost-effective compared to upgrading to a properly sized, modern system.
8. Ductwork Problems
Even a well-functioning system can fail to cool if ducts are leaking, misaligned, or poorly insulated. Cool air may escape before reaching living spaces, resulting in inconsistent temperatures—especially in Savannah homes with attics or older ductwork.
Recommended Actions To Fix Your Air Conditioner When It Is Running But Not Cooling
Homeowner checklist:
- Confirm thermostat is set to “cool” and fan to “auto.”
- Replace filters every 1–3 months; inspect monthly during pollen season.
- Clear debris around the outdoor unit and clean condenser coils.
When to call a professional:
- Evidence of ice on coils or line sets after thawing.
- Unusual sounds, tripped breakers, or outdoor unit not running.
- Suspected refrigerant leak or low refrigerant level.
- Persistent poor cooling despite maintenance.
- System older than 10 years or undersized for your home.
Regular maintenance—including coil cleaning and refrigerant checks—can prevent breakdowns. Booking an annual HVAC inspection before peak summer heat can help ensure your system runs efficiently and keeps your Savannah home cool.
Trust Climatech Air in Savannah, GA For All Your HVAC Needs
Common causes of an AC running but not cooling include thermostat errors, airflow restrictions, refrigerant issues, frozen coils, electrical faults, sizing problems, and duct leaks. While some basic checks and filter changes are DIY-friendly, most complex issues are best handled by certified HVAC technicians. Call our team to learn more today!