Why Is My AC Running But Not Cooling? 7 Common Causes Explained

It is one of the most frustrating calls we get at Texas HVACR Pros: the AC is running, but the house is not cooling. Here in Granbury and Hood County, this is especially serious during summer when temperatures hit triple digits.

1. Dirty or Clogged Air Filter

This is the most common and most overlooked cause. When your air filter is clogged, airflow is severely restricted. In Texas, filters should be changed every 4-6 weeks during heavy use seasons. Check your filter first — it is free to look and often a fresh filter is all you need.

2. Low Refrigerant Leak

Refrigerant absorbs heat from your indoor air and transfers it outside. If your system has a leak, there is not enough to complete the heat transfer process. Signs include warm air from vents, ice forming on the lines, a hissing sound, and higher electric bills. Refrigerant does not run out on its own — if it is low, you have a leak.

3. Frozen Evaporator Coil

Your evaporator coil is inside your air handler. If airflow is restricted or refrigerant is low, the coil can freeze solid. When frozen, no heat transfer can occur. If you suspect a frozen coil, turn the system to fan-only mode to let it thaw, then address the underlying cause.

4. Dirty Condenser Coils

Your outdoor unit releases heat pulled from inside your home. In North Texas, cottonwood seeds and dust can clog condenser coils quickly. When the coils are dirty, the system cannot release heat properly and runs constantly without cooling.

5. Failed Capacitor or Contactor

These electrical components inside your outdoor unit are very common failures in Texas heat. When either fails, the outdoor unit may appear to run but the compressor is not actually working — meaning no cooling is happening. Typically inexpensive to repair when caught early.

6. Compressor Issues

The compressor is the heart of your AC system. A failing compressor means the system simply cannot cool your home. Signs include warm air, tripped breakers, unusual noises, or the outdoor unit shutting off quickly after starting.

7. Ductwork Leaks

Your AC might be working perfectly, but if your ductwork has leaks, the cooled air never makes it to your living spaces. The EPA estimates the average home loses 20-30% of conditioned air through duct leakage. Signs include rooms that never cool properly and high energy bills.

When to Call Texas HVACR Pros

If you have checked your filter and your AC is still not cooling, it is time to call a professional. We serve Granbury, Weatherford, Glen Rose, and all of Hood County with same-day AC repair service. We diagnose the root cause and give you an honest upfront quote before any work begins.