AC Not Cooling
When a Dallas AC runs nonstop through the afternoon but the house keeps drifting a few degrees warmer, the cause we find most often is a refrigerant charge that has slipped low from a slow leak - the system simply can't pull enough heat out of a home when it's 100-plus outside.
Why is my AC running but not cooling?
An AC that runs constantly without cooling is usually low on refrigerant from a slow leak, or unable to shed heat through a dirty or hail-damaged condenser coil. Check the outdoor coil first. Refrigerant is a sealed loop and is never consumed, so a low charge always means a leak somewhere.
Start with the air itself. If the air at your vents is genuinely cold but there just isn't enough of it filling the rooms, the trail leads to airflow - a loaded filter, a matted evaporator coil, or a tired blower. If instead the air coming out is only faintly cool no matter how long it runs, that points the other direction: a low refrigerant charge, a compressor that isn't pumping fully, or a weak run capacitor holding it back. And if the equipment cools fine but a few rooms stay hot, the problem is usually duct losses, not the AC.
What it costs to fix hinges on which of those it is, and on how old your system is. A worn capacitor is an inexpensive, common part. A refrigerant leak is a different conversation: the leak has to be found and sealed, then the charge topped back to spec - and if your unit still runs R-22, which hasn't been produced or imported in the U.S. since 2020, the refrigerant alone has gotten expensive enough that sinking money into a 12-to-15-year-old system rarely pays off. A newer R-410A system usually justifies the repair. A failed compressor almost always tips an aging unit toward replacement.
North Texas is hard on cooling capacity in ways that show up as weak cooling first. Spring hail flattens the thin aluminum fins on your outdoor condenser, and bent fins shed heat poorly, so the unit loses efficiency right before the worst of summer. Cottonwood, pollen, and construction dust from the growing suburbs pack those coils further. Add triple-digit July afternoons and a system that was borderline in June simply can't keep up by August - which is exactly when a hidden charge or airflow problem stops hiding.
How to tell an airflow problem from a refrigerant problem
Feel the air at a supply vent. Cold air but not enough of it points to airflow. Plenty of air that is barely cool points to refrigerant or the compressor. That one check narrows the diagnosis more than any other.
| What you notice | Where it points | What a technician checks |
|---|---|---|
| Air is genuinely cold, but weak | Airflow restriction | Filter, evaporator coil, blower wheel and speed, duct static pressure |
| Good airflow, but only faintly cool | Refrigerant charge or compressor | Suction and head pressure, superheat and subcooling, compressor amp draw |
| Cools fine, but some rooms stay hot | Duct losses, not the equipment | Attic duct runs, insulation, leakage, register balance |
| Fine in the morning, loses ground after noon | Capacity shortfall under load | Condenser coil condition, charge, and the temperature split at peak |
How we pin it down
- Measure the temperature split between return and supply air
- Check the filter and evaporator coil for airflow restriction
- Read refrigerant pressures and superheat/subcooling for charge and leaks
- Inspect the condenser fins for hail damage and dirt
- Test the capacitor and measure compressor amp draw
- Confirm the thermostat call and check ducts for lost cooled air
Guides on this
- What North Texas Hail Does to an Air Conditioner
- How Long Does an AC Actually Last in Texas?
- R-22 and Your Older Dallas AC: What the Phase-Out Actually Means
- Repair or Replace? A Straight Answer for Dallas Homeowners
- SEER2 Explained: What Efficiency Is Worth in a Texas Cooling Season
- Upstairs Hot, Downstairs Cold: Why Two-Story DFW Homes Do This
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Frequently asked questions
Why does my AC keep the house cool all morning but lose ground every afternoon?
That afternoon fade is classic for a system that's short on capacity - a low refrigerant charge, a dirty condenser, or restricted airflow. It copes with mild morning heat, then falls behind once the Dallas sun pushes outdoor temps past 100 and the equipment has to work its hardest. Measuring pressures and the temperature split tells us which limit you're hitting.
Is my system even worth repairing at its age?
It depends on the fault and the refrigerant. A cheap part like a capacitor is worth fixing at almost any age. But a refrigerant leak on an older R-22 unit is where we'll walk you through the math honestly, because the refrigerant is scarce and pricey now - sometimes a repair makes sense, and sometimes putting that money toward a new, more efficient system saves you more over a Texas summer. No pressure either way.
Could this spring's hail be why it isn't cooling well?
It can absolutely be a factor. Hail bends the condenser fins that release heat outdoors, and a unit that can't shed heat efficiently struggles most on the hottest days. It rarely stops cooling on its own, but paired with a dirty coil or a marginal charge it's often the tipping point. We check for fin damage as part of the diagnosis.
My electric bill jumped this summer - is that connected?
Very possibly. A system that's low on charge, dirty, or starved for airflow runs far longer to reach the same temperature, and that extra runtime lands on your bill. Fixing the underlying cause usually brings both your comfort and your energy use back in line.
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