AC Blowing Warm Air Only

AC Blowing Warm Air Only

Air Conditioning Repair | AC Blowing Warm Air

Life without air conditioning is almost unimaginable for most of us. When the AC is blowing warm air, air conditioning repair isn’t optional, it is a necessity. A broken air conditioner on hot, humid days is more than an inconvenience for those with heart and respiratory problems, it can be downright deadly.

Quite often, the AC blowing warm air is due to simple problems that a homeowner can take care of without calling an HVAC technician for air conditioning repair in Katy.


The thermostat is a frequently overlooked component of the heating and air conditioning system. It will eventually have to be replaced, and is also a source of numerous problems due to our own forgetfulness. First, ensure the thermostat is set at Cool. Perhaps you or another family member opened a window and turned the cool/heat/off function to off and the manual fan to on, bringing fresh air into the home. It is easy to be distracted and forget to return it to cool and the fan to auto.

When this occurs the fan is blowing constantly, and when the compressor isn’t operating, the fan continues to blow making it appear the AC is blowing warm air. It is a common mistake, so don’t feel bad if this is the cause.

Next, check the temperature. For example, if the thermostat is set at 80 degrees, and the inside temperature is 78, the unit will not cut on unless the temperature reaches 81 or above. Again, if the fan is set to manual rather than automatic, it will blow warm air until the compressor runs producing cold air.

After ensuring the fan is on automatic, turn the thermostat down to trigger the system to cut on, if the AC is blowing warm air only, check the following:

Check the Filter & Breaker

Check the air filter, and ensure it is clean. A dirty, clogged filter can block the proper air flow, causing the system to overheat and throw a breaker. Some split systems have a switch inside the indoor blower component of the system. It typically looks similar to a light switch. Furthermore, some systems have breakers inside the indoor portion of the system. If one or more of these have tripped, you may have fan operation only, resulting in the AC blowing warm air or no operation at all.

If any of these have been thrown, turn the system off at the thermostat and turn any thrown switch and breakers back on. Turn the system back on at the thermostat. If nothing occurs, and the set temperature is lower than the room temperature, proceed to the next step.

The External Breaker

Check the breaker at the outdoor condenser. There should be a box containing a breaker located near the condenser unit. If the breaker is off, turn it back on. Numerous factors can cause a thrown breaker, for example, the power service may have fluctuated initiating a temporary overload and throwing of the breaker. If these steps fail to restore cooling call Cypress Heating and Air Conditioning and let us know that your AC is blowing warm air.

Tips for Best Performance

Do not block the area around the air return (the area where the filter is located) to avoid impairing its airflow, and potential overheating. Overheating can cause a breaker to be thrown, resulting in the AC blowing warm air.

Keep registers’ free of obstruction. Drapes, furniture or other objects covering the registers will affect the system and can cause problems within the HVAC system itself.

The HVAC system requires annual maintenance for proper operation and optimal performance. Over time dust and grime collect on cooling coils, especially if the filter hasn’t been routinely changed. Dirty coils will result in poor performance and other problems, including the AC blowing warm air. Your technician will assess your coils during routine maintenance and clean them if required. Check the filter monthly, and change when soiled, even if they are three month filters.

When your AC is blowing warm air, contact Cypress Heating and Air Conditioning’s certified and licensed HVAC technicians for professional air conditioning repair. You can count on Cypress’s dedicated professionals for superior service. We serve Katy, Plano and the surrounding areas, and are a member of the BBB with an A+ rating.