Most Common Reasons Your AC Isn't Cooling
An air conditioner that runs continuously without cooling the house is one of the most frustrating HVAC problems — especially during an Ohio summer. Here are the most common causes, starting with what you can check yourself.
1. Dirty or Clogged Air Filter
A heavily restricted air filter starves the evaporator coil of airflow. Without adequate airflow, the coil can't absorb heat from your home's air. The result is an AC that runs and runs while barely cooling anything. This is the first thing to check. If the filter is gray and dense, replace it. Give the system 20 to 30 minutes to recover after replacing.
2. Low Refrigerant
Refrigerant is the chemical that absorbs heat inside your home and releases it outside. When the level is low — always due to a leak, never normal depletion — the system can't move heat effectively. Symptoms include ice on the refrigerant lines, warm air from vents, and hissing or bubbling sounds. Adding refrigerant without finding the leak is a temporary fix — the leak must be located and repaired first.
3. Frozen Evaporator Coil
The evaporator coil inside your air handler can freeze when airflow is restricted or refrigerant is low. Ice on the coil blocks airflow entirely, and the system blows warm or room-temperature air. If you see ice on the refrigerant lines, turn the system to Fan Only — not Off — and let it thaw for 2 to 3 hours before restarting. If it freezes again, there's an underlying issue requiring a technician.
4. Dirty or Blocked Outdoor Condenser Unit
The outdoor unit releases the heat your AC pulls from inside your home. When the condenser coils are coated with dirt, grass clippings, or cottonwood, or when the unit is surrounded by overgrowth, it can't reject heat effectively. You can rinse the condenser coils gently with a garden hose — spray from inside outward. Make sure nothing is growing within two feet of the unit.
5. Thermostat or Electrical Issues
Confirm the thermostat is set to Cool, the temperature is set below the current room temperature, and the fan is set to Auto rather than On. A failed run capacitor — a common summer repair — causes the compressor or fan motor to not start properly, leaving the system running with reduced or no cooling. This is an inexpensive repair when caught early.
6. Ductwork Leaks
If your home has certain rooms that never seem to cool even when other areas are comfortable, leaking ducts are a likely cause. Conditioned air escapes into unconditioned attic or crawl space before reaching those rooms. This is a less urgent repair but adds up in energy cost over a summer season.
What You Can Check Before Calling
- Air filter — replace if clogged or overdue
- Thermostat — set to Cool, temperature below room temp, fan on Auto
- All supply vents open and not blocked by furniture
- Outdoor unit — clear of debris, at least 2 feet of clearance
- Check refrigerant lines for ice — if frozen, switch to Fan Only
- Circuit breaker for the AC — reset if tripped
When to Call a Technician
Call Licking County HVAC if the system still isn't cooling after working through the checklist, if the coil refreezes after thawing, if you hear grinding or hissing sounds, or if you suspect a refrigerant leak. We serve Newark, Heath, Granville, Pataskala, and all of Licking County with same-day AC repair and 24/7 emergency service.