AC Running but Not Cooling? What to Check in Houston

Draft for technical review · General information, not an equipment diagnosis.

When your air conditioner seems to run continuously but the house stays warm, it’s easy to assume the system needs replacing. But running without cooling is a symptom, not a diagnosis. A number of different issues can affect cooling, and many require a professional assessment to distinguish.

Indoor Air, Inc. serves homes and businesses throughout Greater Houston. We take a repair-first approach when a repair is an appropriate option.

Need service? Call (281) 933-8080 or request AC service. If the problem is time-sensitive, call; after-hours and weekend calls are answered, and dispatch is subject to availability.

Before You Call: Common Homeowner Checks

Use normal homeowner controls and safely accessible areas only. If you see smoke, sparks, damaged wiring or water near electrical equipment, keep clear and stop troubleshooting. A thermostat set to OFF does not disconnect electrical power.

1. Check the breakers

Check whether the labeled AC and indoor-unit breakers appear tripped. Do not remove the electrical panel cover, open equipment cabinets or touch wiring. If a breaker is tripped, leave the system off and call for guidance. Never repeatedly reset a breaker that trips.

2. Check the return air filter

A dirty or clogged return air filter can restrict airflow. If the filter is safely accessible and intended for homeowner replacement, turn the system off and replace it with the specified size and type according to the manufacturer’s instructions. Keep accessible supply and return grilles clear of furniture.

3. Try one thermostat restart after a power interruption

If power is stable and there is no ice, water leak, tripped breaker or other sign of a fault, turn the thermostat’s system setting to OFF for about five minutes. Then select COOL, set the temperature below the room temperature and allow any built-in restart delay to finish.

This can help after a power interruption, but it does not repair an underlying fault. If cooling does not return, call us rather than repeatedly cycling the system.

4. Look for ice on the refrigerant lines

From a safe, ground-level position, look for ice on the visible refrigerant lines at the outdoor condensing unit. Do not remove panels, touch the lines, chip off ice or apply heat.

Ice can result from restricted airflow, including a clogged filter, or from a refrigerant or other equipment problem. Ice alone does not prove that the system is low on refrigerant.

If the filter is dirty: turn cooling OFF and replace the homeowner-accessible filter as directed by the manufacturer. With no water overflow or electrical concern, set the thermostat fan to ON to help thaw the ice, provided the indoor blower operates normally. Allow the ice to thaw completely; this can take several hours. If the manufacturer’s instructions permit restarting, return the fan to AUTO, select COOL and monitor operation. If ice returns or cooling is poor, turn cooling off and call.
If the filter is clean, inaccessible or you are unsure: leave cooling OFF and call for service. The fan may be set to ON for thawing only if it operates normally and there is no water overflow or electrical concern.
If water leaks or overflows, or the fan does not run normally: turn the system off and call. Do not leave it thawing unattended where water could cause damage.

Do not attempt to add refrigerant yourself.

5. Check for dripping from the emergency drain line

If cooling stops and later starts again, look from a safe location for water dripping from the secondary or emergency condensate drain outlet, if you know which outlet it is. Do not climb to inspect it.

Water from that outlet can indicate a blocked primary drain or another drainage problem. A float safety switch may be interrupting cooling to prevent an overflow. Normal drainage from the primary condensate outlet is different; if you cannot identify the outlet, call us.

If the emergency outlet is dripping, or you see a full drain pan, indoor water leakage or ceiling staining, turn cooling OFF and call for service. Do not bypass the float switch or repeatedly restart the system.

Still need help? Call Indoor Air at (281) 933-8080. Tell us what you checked and what happened. You do not need to diagnose the system before calling.

Common Categories of Cooling Problems

The following are possible categories, not a remote diagnosis:

Restricted airflow

A dirty filter or another airflow restriction can make it harder for a system to cool properly. Airflow problems are not always visible from the thermostat or a single vent.

Controls or thermostat issues

Incorrect settings, sensor problems or other controls can prevent the system from operating as intended. A technician may need to evaluate the actual equipment response rather than assuming the thermostat is the entire problem.

Outdoor or indoor equipment faults

A cooling system relies on multiple components working together. Mechanical and electrical issues can create similar comfort symptoms even when some equipment appears to be running.

Refrigerant-system concerns

A system’s refrigerant circuit needs specialized handling. Suspected leaks or performance faults should be evaluated by appropriately qualified service personnel; don’t try to add refrigerant or open the system yourself.

Heat gain, uneven cooling or other building conditions

Long cooling cycles can reflect the building load and airflow pattern as well as the equipment. If one room is uncomfortable while another is fine, tell the office where the issue is occurring and whether it is new or recurring.

What Information Helps With a Service Request?

You don’t need to diagnose the problem yourself. It helps to describe:

Whether the system is running, off or cycling repeatedly.
Whether air from the vents feels warm, weak or simply not as cool as expected.
When the problem started and whether it affects all or part of the building.
Any thermostat alerts, unusual sounds, visible water or recent service.
The service location ZIP code and best callback number.

Is This a Repair or Replacement Problem?

The answer depends on what has failed and the condition of the equipment. A known, repairable component issue is a different situation from repeated failures or broader deterioration. Read Should You Repair or Replace Your AC? for an estimate-comparison framework.

Houston’s Long Cooling Season Makes Clear Answers Important

AC trouble is disruptive at home and at work, especially during extended warm weather. A service conversation should focus on identifying the problem, explaining available options and helping you decide on the next step rather than guessing from a search result.

Explore AC Repair Services | Call (281) 933-8080

Office hours: Monday–Friday, 7:30 a.m.–4:00 p.m. After-hours and weekend calls are answered; technician dispatch is subject to availability.

AC Running but Not Cooling? Here's Where to Start.