Few things are more frustrating than an air conditioner that runs constantly — and still leaves your home hot. This is actually one of the most common HVAC complaints we receive, particularly during the first real heat wave of summer. Here's a systematic breakdown of the most common causes.
1. Dirty Air Filter — Check This First
A severely clogged air filter restricts airflow to the evaporator coil, reducing efficiency dramatically and eventually causing the coil to freeze. Check your filter before calling anyone. If it's gray and matted, replace it and give the system 30 minutes to recover. This solves the problem in a surprising number of cases.
2. Low Refrigerant (Refrigerant Leak)
Your AC doesn't "use up" refrigerant — it circulates in a closed loop. If refrigerant is low, there's a leak. Low refrigerant causes the system to run endlessly without reaching temperature, frost on the refrigerant lines, and eventually compressor failure. This requires a licensed HVAC technician with the right tools.
3. Frozen Evaporator Coil
If you see ice on the indoor unit's copper lines or on the unit itself, the evaporator coil has frozen. This is caused by restricted airflow (dirty filter, blocked vents) or low refrigerant. Turn the system to "fan only" for 2-3 hours to thaw, then call for service.
4. Dirty Condenser Coil
The outdoor unit's condenser coil releases heat from your home into the outdoor air. When it's coated with dirt, grass clippings, or cottonwood fluff, it can't transfer heat effectively — system efficiency plummets. Annual cleaning is part of every HVAC Coalville tune-up.
5. Failing Compressor
The compressor is the heart of your AC system. When it starts to fail, it may run but produce insufficient pressure to cool the refrigerant properly. Compressor failure is an expensive repair — it's often more cost-effective to replace the system.
6. Thermostat Issues
Confirm the thermostat is set to "cool" (not "fan"), that the setpoint is lower than the current room temperature, and that the display shows the correct current temperature. A miscalibrated or faulty thermostat can fool you into thinking the system is working when it's running the fan only.
7. Duct Leaks
If your ductwork has significant leaks — which is common in homes with flex duct in attics or crawl spaces — conditioned air escapes before reaching your living spaces. Signs include rooms that are consistently harder to cool and high energy bills.
8. Undersized System
On extremely hot days (95°F+), even a properly functioning system may struggle if it was undersized to begin with. An AC that runs 100% of the time without reaching setpoint on the hottest day of summer is likely undersized for your home's cooling load.
What to Do
Start with the filter. Then check that all supply vents are open and unobstructed. If the system still isn't cooling after 30 minutes, call (435) 244-1090. Our technicians carry the tools to diagnose refrigerant levels, electrical faults, and airflow problems on the same visit.
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