Why is my AC running constantly but the house is still warm?

Constant running with poor cooling usually means capacity is short: restricted airflow, low charge, a dirty condenser coil or a compressor that is not pumping well. It can also happen when a system is simply undersized for a very hot afternoon, but a sudden change points to a fault.

Could low refrigerant just be normal loss over time?

No. A sealed refrigerant circuit does not consume refrigerant. Low charge means there is a leak, and adding refrigerant without finding it is a temporary fix that repeats.

Will changing the filter fix it?

Sometimes, if the filter is badly loaded and the coil has not yet frozen. It is a safe first step and it removes one variable before a diagnosis.

Should I lower the thermostat further to cool faster?

No. The system removes heat at a fixed rate. A lower setpoint only makes it run longer, which can worsen a freeze-up or hide the real fault.

Symptom diagnosis

AC Not Cooling in Gainesville, FL

A system that runs without cooling is doing part of its job. The blower moves air, but heat is not leaving the house — which narrows the problem to airflow, the refrigerant circuit, the compressor or the controls telling them what to do.

Here is how those causes differ, what you can safely check, and what a technician measures to separate them.

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What the symptom tells you

Feel the air at a supply vent. A properly operating system usually delivers air noticeably cooler than the return air — often in the range of 15 to 20 degrees cooler, though that varies with humidity and conditions.

Air that is only a few degrees cooler points toward low refrigerant charge, a restricted metering device, a dirty coil or a compressor that is not pumping. Air that feels cool but weak points toward airflow. No cool air at all with the fan running points toward the outdoor unit or compressor not operating.

Common causes

Restricted airflow

A loaded filter, dirty evaporator coil or dust-caked blower wheel reduces the air crossing the coil. Cooling capacity drops and the coil can eventually freeze.

Low refrigerant from a leak

Refrigerant is not consumed. If the charge is low, it left through a leak — a coil, a fitting, a line set rub-through or a service valve.

Outdoor unit not running

A failed capacitor, contactor, fan motor or tripped disconnect leaves the indoor blower circulating air with nothing removing heat from it.

Compressor not pumping

A compressor can run electrically and still fail to compress. Pressures that sit close together with low amp draw are a strong indicator.

Dirty condenser coil

Grass clippings, pollen and dryer lint on the outdoor coil trap heat the system needs to reject. Performance falls sharply on the hottest days.

Thermostat or control fault

A miswired or failing thermostat, a bad control board or a stuck relay can run the fan without ever calling for cooling.

Safe checks you can do now

Confirm the thermostat is set to COOL and the fan is set to AUTO or ON.
Lower the setpoint a few degrees and listen for the system to start.
Check that the thermostat has power — a blank screen often means dead batteries or a tripped safety switch.
Look at the accessible air filter and replace it if it is visibly loaded with dust.
Verify the indoor unit's service switch (it looks like a light switch near the air handler) was not flipped off.
Walk the house and open blocked supply and return vents.
Step outside and note whether the condenser fan is spinning.
Look for standing water, drips or stains near the indoor unit.

If the copper lines or indoor coil are iced, shut the cooling off and run the fan only. Running a frozen system risks compressor damage and water overflow.

What a technician measures

Supply and return air temperatures, plus the temperature split across the coil.
Static pressure and airflow to confirm the blower is moving the design volume of air.
Suction and liquid pressures, then calculated superheat and subcooling.
Compressor amp draw compared with the data plate rating.
Capacitor capacitance and contactor condition at the outdoor unit.
Condenser and evaporator coil cleanliness, and refrigerant line insulation.

Gainesville context

In humid weather a system uses much of its capacity removing moisture, so a slightly weak system that coasted through spring shows up as "not cooling" in July. Marginal charge and dirty coils often surface exactly then.

Homes with attic air handlers — common in newer neighborhoods off Newberry Road and in Southwest Gainesville — also lose capacity through hot attic ductwork, which makes weak cooling feel worse in upstairs rooms.

Frequently Asked Questions

Why is my AC running constantly but the house is still warm?: Constant running with poor cooling usually means capacity is short: restricted airflow, low charge, a dirty condenser coil or a compressor that is not pumping well. It can also happen when a system is simply undersized for a very hot afternoon, but a sudden change points to a fault.
Could low refrigerant just be normal loss over time?: No. A sealed refrigerant circuit does not consume refrigerant. Low charge means there is a leak, and adding refrigerant without finding it is a temporary fix that repeats.
Will changing the filter fix it?: Sometimes, if the filter is badly loaded and the coil has not yet frozen. It is a safe first step and it removes one variable before a diagnosis.
Should I lower the thermostat further to cool faster?: No. The system removes heat at a fixed rate. A lower setpoint only makes it run longer, which can worsen a freeze-up or hide the real fault.

Prefer to talk it through? Call 352-707-8045 or send a service request.

AC Trouble in Gainesville?

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