Why Is My AC Running But Not Cooling?

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Nothing feels worse on a hot Texas day than realizing your air conditioner is running but your home still feels warm and sticky. If your AC is blowing air that is anything but cool, you are not alone. This is one of the most common issues homeowners deal with, especially in coastal areas like Port Aransas, where heat, humidity, and salt air can push HVAC systems to their limits.

So why is your AC running but not cooling your home? Let’s break down the most common reasons and what you can do about them.

1. Dirty or Clogged Air Filter

Your air filter might seem small, but it has a big job. When it gets clogged with dust, sand, pet hair, or coastal humidity gunk, airflow is restricted. Your AC may still run, but air cannot move across the evaporator coils properly, which means warm air stays warm.

Fix:
Check your air filter monthly and replace it every 1–3 months. Coastal homes sometimes need replacements even more often.

2. Low Refrigerant Levels

If your AC is blowing warm air, low refrigerant is a likely culprit. Refrigerant removes heat from your home. When levels drop because of a leak or normal wear, your air conditioner loses its cooling power.

Signs you may have a refrigerant issue:

AC runs constantly
Vents blow warm or room-temperature air
Ice forms on the refrigerant lines
Hissing sounds near the outdoor unit

Fix:
Only a licensed HVAC technician can handle refrigerant. Call Highland AC – Coastal Bend for a system inspection and leak repair.

3. Frozen Evaporator Coils

Even though it sounds odd, your AC coils can freeze even in hot weather. When airflow is restricted or refrigerant is low, the evaporator coil can become so cold that condensation turns to ice. Once frozen, the coil cannot absorb heat, and your home stops cooling.

Fix:
Turn off your AC and run the fan to help melt the ice. Do not chip it off. After the coil thaws, call a technician to diagnose the underlying cause.

4. Dirty Outdoor Unit

The outdoor condenser unit releases heat from your home. Along the Texas coast, it is common for salt, sand, grass clippings, and debris to clog the fins. When the condenser cannot release heat properly, your AC will run but never cool efficiently.

Fix:
Gently rinse the outdoor unit using a hose, avoiding high pressure. If you haven’t had a maintenance cleaning recently, schedule one with our team.

5. Thermostat Problems

Sometimes the issue is as simple as thermostat confusion. Incorrect settings, a dead battery, or a malfunctioning sensor can make it seem like your AC is not cooling.

Fix:
Check your thermostat settings, replace batteries if needed, and make sure the mode is set to “Cool,” not “Fan.”

6. Leaky or Damaged Ductwork

If cool air is escaping into your attic before it reaches your rooms, your AC may run for hours without cooling the house. Coastal homes often deal with ductwork deterioration from humidity and corrosion.

Fix:
Have your ductwork inspected for gaps, leaks, or damaged insulation.

7. Your AC Unit May Be the Wrong Size

If your system is too small for your home, especially after additions or remodels, it will run nonstop and struggle to cool. If it is too large, it will “short cycle,” shutting off before completing a full cooling cycle.

Fix:
A load calculation from Highland AC can determine if your system is properly sized.

Call Highland AC – Coastal Bend When Your AC Stops Cooling

Your air conditioner should keep you comfortable even in the toughest Texas heat. If it’s running but not cooling, our skilled technicians can diagnose the issue quickly and get your home back to the cool comfort you deserve.

From clogged filters to refrigerant leaks to full system failures, Highland AC in Port Aransas is here to help with honest service, fast repairs, and coastal-ready HVAC expertise.

Stay cool, stay comfortable, and call Highland AC – Coastal Bend for reliable AC repair today.