North Carolina residents know the summer heat can be brutal. There’s nothing worse than coming in from a hot day, turning up the air conditioner, and finding warm air coming from the vents when it should be cold. This happens most often during the hottest months of the year because your cooling system works hard for long hours every day.
If your air conditioner’s running but not cooling your home, it’s important to address the issue early. Otherwise, a small problem could become a big, expensive issue. At Thermo Direct, our HVAC maintenance experts will find out why your AC’s not blowing cold air and fix it for you right away.
Top Reasons Your AC Is Running But Not Cooling
The following are the most common answers to the question “Why is my AC not cooling my home?”
- Dirty or clogged air filters: Dirt, dander, and particles restrict airflow, reduce cooling capacity, increase energy use, and strain the fan motor. Change filters every 90 days — or every 30-60 days if AC runs continuously.
- Thermostat issues: Setting the thermostat to “fan” instead of “cool” results in warm airflow. A faulty sensor or calibration issue can also disrupt cooling.
- Refrigerant leak or low refrigerant levels: Refrigerant leaks cause reduced cooling, hissing sounds, or ice buildup on evaporator coils. Refrigerant is toxic, flammable, and regulated, so professional repair is required immediately.
- Frozen evaporator coil: Poor airflow or low refrigerant causes condensation and ice buildup, halting cooling and risking internal damage.
- Dirty condenser coils: Outdoor condenser units clogged with debris, dust, or leaves suffer restricted airflow, reducing cooling capacity.
- Electrical issues or tripped breakers: Electrical surges or faults may trip breakers, causing the outdoor unit to shut off while the indoor unit remains on. Professional HVAC diagnosis and repair is advised.
- Leaky or damaged air ducts: Cracks or holes in air ducts allow cooled air to escape, causing warm airflow from vents and inefficient cooling.
- Old or undersized AC system: Weak airflow, frequent repairs, and high energy bills signal an undersized or aging AC. Systems older than 15 years or incorrectly sized units typically need replacement despite regular maintenance.
DIY Troubleshooting Tips for Homeowners
If you prefer to troubleshoot your AC issues before doing an internet search for HVAC technicians near you, try the following DIY tips:
- Check thermostat settings: Confirm settings are correct. Replace batteries or recalibrate if needed. Call a pro if problems persist.
- Inspect and replace the air filter: Dirty filters restrict airflow and cause warm air. Regularly clean or replace filters, especially in summer.
- Look for ice or water near the unit: Ice buildup or leaks indicate issues. Shut off the AC, allow the ice to melt, and call a technician to diagnose underlying causes.
- Clear debris around the outdoor unit: Remove leaves and dirt by hand. Gently wash with a sponge and soapy water — avoid power washing. Schedule a tune-up for thorough cleaning.
- When to call an HVAC pro: If DIY steps fail, you hear odd noises, smell bad odors, notice electrical issues, ice buildup, water leaks, or rapid cycling, contact Thermo Direct.
How This Affects Your Energy Bill and Comfort
Cooling issues indicate there’s strain on the HVAC system, which causes a shorter lifespan and higher repair costs. You’ll have poor humidity control in your house and difficulty controlling in-home comfort levels.
Preventing Cooling Issues With Regular AC Maintenance
At Thermo Direct, we do AC repair near you, including emergency AC repair and more. To prevent breakdowns from happening in the first place, schedule regular maintenance.
What’s included in a maintenance visit?
During a regular maintenance visit from Thermo Direct, our technicians thoroughly inspect your entire air conditioning system to optimize performance and efficiency. This includes checking and replacing air filters as needed, assessing refrigerant levels, inspecting for leaks, and carefully cleaning both the evaporator and condenser coils. Additionally, we’ll test electrical connections, calibrate your thermostat, evaluate airflow, lubricate moving components, and ensure your AC is operating safely, reliably, and at peak efficiency.
How often should you schedule maintenance?
We recommend scheduling HVAC maintenance visits twice per year — ideally once in the spring before the summer heat arrives and again in the fall to prepare for winter temperatures. Regular, biannual maintenance ensures your air conditioning system stays clean, efficient, and reliable throughout every season. It also helps catch minor issues before they become costly repairs, extends the lifespan of your HVAC equipment, and maintains optimal indoor air quality and comfort year-round.
Schedule an AC Inspection in Raleigh, NC, Today
At Thermo Direct, we make expert HVAC service accessible for Raleigh homeowners by offering flexible financing options and valuable coupons. Whether you need a routine tune-up, an in-depth system diagnosis, or urgent AC repairs, our professional team is here to ensure your home stays comfortable year-round. Don’t wait until minor issues become major problems — contact us today to schedule your appointment and enjoy reliable, energy-efficient cooling.
Frequently Asked Questions
Is it safe to keep running my AC if it’s not cooling?
Not usually. If the AC is already straining, running it more may cause a costly breakdown, motor burnout, or worse. Turn it off and call for help.
Why does my thermostat say it’s cooling, but it’s still hot inside?
There could be a thermostat malfunction, or it may need to be calibrated. Contact an HVAC expert at Thermo Direct for assistance.
How do I reset my air conditioner if it’s not cooling?
Check if your AC has a reset button, or turn the power off completely at the circuit breaker, wait 10 minutes, then turn it back on. If these steps don’t work, call our team to find the root cause of the issue.
