Few things are more frustrating on a 105-degree Fresno afternoon than an air conditioner that seems to be running fine — you can hear it, you can see the fan spinning outside — but your home just will not get cool. The thermostat says 85 degrees even though it has been set to 74 for the past three hours.
This is a surprisingly common situation, and it almost always has a diagnosable cause. Here is a breakdown of what is most likely going on and what you should do about it.
Low or Leaked Refrigerant
Refrigerant is the substance your air conditioner uses to absorb heat from inside your home and release it outside. If refrigerant levels are low — usually because of a leak rather than normal depletion — the system loses its ability to transfer heat effectively. The result is an AC that runs constantly without delivering real cooling.
Signs that refrigerant may be the issue:
- Ice forming on the refrigerant lines or evaporator coil
- A hissing or bubbling sound near the unit
- The air from the vents is not noticeably cold even after extended runtime
Refrigerant is not something that can be topped off by a homeowner. Handling it requires EPA certification, and a responsible technician will also locate and repair the source of the leak rather than simply recharging the system.
Dirty Evaporator or Condenser Coils
Your AC system has two sets of coils — an evaporator coil inside the air handler and a condenser coil in the outdoor unit. Both need to be reasonably clean to transfer heat effectively.
When evaporator coils get covered in dust and debris, they cannot absorb heat from the indoor air efficiently. When condenser coils are dirty — often from yard debris, cottonwood fluff, or just accumulated grime — the system struggles to release heat outside. Either condition results in reduced cooling performance, even while the system runs continuously.
Coil cleaning is part of a standard preventive maintenance visit and is one of the best reasons to schedule a tune-up before Fresno's summer heat arrives.
Clogged Air Filter
A severely restricted air filter does not just reduce airflow — it can cause the evaporator coil to freeze over. When the coil is encased in ice, it cannot absorb heat from the air moving over it, and your system effectively stops cooling even though it keeps running.
If your AC is running but not cooling, check your filter first. If it is heavily clogged, replace it and turn the system off for a few hours to allow the ice to melt. Once the coil thaws, restart the system with the new filter in place and see if cooling performance returns.
If the coil freezes again even with a clean filter, there is likely an underlying refrigerant or airflow issue that needs professional attention.
Thermostat Problems
Sometimes the issue is not mechanical at all — it is the thermostat. A thermostat that is reading the room temperature inaccurately may not be calling for as much cooling as the actual conditions require. It might also be wired incorrectly, failing to communicate the right signals to the system.
If your home feels warm but the thermostat is displaying a temperature that seems lower than what you feel, suspect a calibration or placement issue. Thermostats located near heat sources — direct sunlight, lamps, appliances — will read higher than the actual room temperature and may cycle the system off prematurely.
Duct Leaks or Inadequate Duct Design
Even if your AC is working perfectly, you may feel like it is not cooling if a significant portion of the conditioned air is escaping into your attic or crawl space through leaky ducts. Duct leaks are common in older homes and can account for a meaningful loss of cooling efficiency.
Symptoms include rooms that never seem to reach the set temperature, high energy bills despite continuous runtime, and noticeable temperature differences between rooms at the same level of the house.
The System Is Too Small for Your Home
If you have recently added square footage, converted a garage, or moved into a home that was previously maintained with different usage patterns, the existing AC system may simply not be sized to handle the cooling load. This is particularly relevant in newer Clovis developments where open floor plans and larger square footage demand properly sized equipment.
An undersized system will run almost continuously in summer without ever catching up — which is hard on the equipment and hard on your energy bill.
What to Do Next
If your AC is running but not cooling, start with the basics: check your filter, make sure the thermostat is set correctly, and look for any visible ice on the refrigerant lines. If none of those simple checks resolve the problem, it is time to call a professional.
JC Melton Air Conditioning has been diagnosing cooling problems in Fresno and Clovis for more than 70 years. Our NATE Certified and EPA Certified technicians can identify the root cause of the problem — not just mask the symptom — and give you an honest recommendation on the most cost-effective solution.
Call us at (559) 268-6286 or request a service visit online before the situation gets worse during the next heat wave.