Why Is My AC Blowing Warm Air? Common Causes and Solutions

Nobody wants to come home to an air conditioner blowing warm air on a hot Texas summer day. If your AC is running but not blowing cold air, you may be wondering what went wrong and whether you can fix the problem yourself.

The good news is that some AC problems have simple solutions. Before calling for professional air conditioning repair, there are a few basic troubleshooting steps you can safely try.

If your AC is still blowing warm air after checking these items, it's time to call a professional. Forrest Air can diagnose the problem and get your system back to cooling your home.

What to Check If Your AC Is Blowing Warm Air

• Check Your Thermostat Settings

  • Start with the simplest possibility: your thermostat settings.

  • Make sure your thermostat is set to "Cool" rather than "Heat" or "Fan," and check that the temperature is set lower than the current temperature inside your home. If your thermostat has a fan setting, "Auto" is typically the best choice.

  • If the thermostat is set to "On," the fan will continue blowing air even when the AC isn't actively cooling. This can improve air circulation in the home but also sometimes make it seem like your AC is blowing warm air.

• Check Your Air Filter

  • A dirty or clogged air filter can restrict airflow through your HVAC system and contribute to cooling problems. If your filter looks gray, dusty, or clogged, replace it with a clean filter of the correct size.

  • If the filter is VERY dirty this may have caused the coil to ice up and block the airflow. You may see some ice forming around the large copper pipe coming out of the indoor coil. If this happens the best thing to do is turn your thermostat to off and your fan to on to help thaw the ice better. Sometimes it helps to have some towels on hand as the drain pan doesn't always catch all the melting ice. Leave the system in this state for about 1-2 hrs and then turn the mode back to cool and the fan to auto. 

  • Regularly changing your air filter can help maintain proper airflow and keep your AC system operating efficiently.

  • If an ac system is working properly typically you will get 15-20 degrees temperature difference between the air going in the return and the air coming out of the supply. If you have a thermometer this is a great thing to check.

• Clear Debris From the Outdoor Unit

  • Take a look at your outdoor AC unit. Leaves, grass clippings, dirt, and other debris can accumulate around the unit and restrict airflow.

  • If you see debris around the outdoor unit, carefully remove it from the surrounding area. Make sure if you are using a water hose to clean the coil that you spray in a downward angle so as not to push debris further into the coil.

  • If your outdoor unit is very dirty and restricting airflow it can cause high pressure that will trip a sensor and turn your system off.

  • The best way to clean your coil is to have one of our technicians disassemble the unit and clean it from the inside out. Give us a call to get on the schedule.

• Check Your Circuit Breaker

  • Your air conditioner depends on electricity to operate both its indoor and outdoor components. Check your home's electrical panel to see if the circuit breaker connected to your AC system has tripped.

  • If the breaker has tripped, you can reset it once. If it trips again, don't continue resetting it. A repeatedly tripping breaker could indicate a more serious electrical or mechanical problem that requires professional attention.

• Communication systems

  • If your system is a high efficiency communicating system then sometimes the circuit boards can have a malfunction and get out of sync.

  • Try turning all the breakers to the indoor and outdoor units off for 30 seconds and then turn it back on and test the system. If this doesn't fix it then give us a call, we have the tools and skills you need to diagnose even complicated issues like this.

Common Reasons Your AC Is Blowing Warm Air

If you've checked the basics and your air conditioner is still blowing warm air, the problem may require professional diagnosis and repair.

• Low Refrigerant Levels

  • Your AC system uses refrigerant to absorb heat from the air inside your home and transfer that heat outdoors. If your system has low refrigerant, it may not be able to cool your home effectively.

  • Contrary to a common misconception, an AC system does not normally "use up" refrigerant. Low refrigerant is often a sign of a refrigerant leak somewhere in the system that needs to be addressed.

  • Solution: Refrigerant problems require professional AC service. A Forrest Air technician can identify the source of a refrigerant leak, make the necessary repairs, and recharge the system to the proper level.

• Frozen Evaporator Coils

  • Frozen evaporator coils can prevent your AC system from properly absorbing heat from your home's indoor air. When the coils freeze, It can reduce your airflow or block it completely.

  • Frozen coils are often a symptom of another issue, such as restricted airflow from a dirty air filter or indoor coil, a restriction in the metering device or filter drier, or low refrigerant levels.

  • Solution: If you suspect your evaporator coil is frozen, turn off your AC and turn the fan switch on to allow the system to thaw more quickly. When the coil thaws the water that is produced can overflow out of the unit so have towels ready if necessary, make sure the coil is completely thawed and contact a professional to identify and repair the underlying cause.

• Compressor Problems

  • The compressor is one of the most important components of your air conditioning system. It circulates refrigerant through the system so heat can be removed from your home.

  • If the compressor experiences an electrical or mechanical failure, your AC may continue to run without producing cold air.

  • Solution: Compressor problems require professional diagnosis. A Forrest Air technician can inspect your system, determine whether the compressor is the source of the problem, and recommend the appropriate repair.

• Electrical Problems

  • Your AC system relies on several electrical components to operate safely and effectively. A tripped circuit breaker, blown fuse, faulty wiring, or another electrical issue can prevent your system from cooling properly.

  • Solution: You can check your home's electrical panel for a tripped AC breaker and reset it once. If the breaker trips again, leave it off and contact a professional. Electrical issues can be dangerous and should be diagnosed and repaired by a qualified HVAC technician.

• A Faulty Thermostat

  • Sometimes, the problem isn't with your air conditioner itself; it's with the thermostat.

  • A malfunctioning thermostat may not accurately read the temperature in your home or properly communicate with your AC system. As a result, your air conditioner may not run when it should or may fail to cool your home to the temperature you've selected.

  • Solution: If your thermostat appears to be malfunctioning or your AC isn't responding to temperature adjustments, a professional HVAC technician can test the thermostat and determine if it needs to be replaced.

When Should You Call an HVAC Professional?

If your AC is blowing warm air after you've checked the thermostat, air filter, outdoor unit, and circuit breaker, it's best to stop troubleshooting and call a professional.

Continuing to run an air conditioner that isn't cooling properly can potentially worsen an existing problem, particularly if the system has low refrigerant, frozen coils, or a mechanical issue.

Forrest Air can inspect your system, identify the cause of the problem, and recommend the best solution to restore cool air to your home.

Whether you're in Weatherford, Aledo, Hudson Oaks, Willow Park, Benbrook, Brock, Granbury, or Fort Worth, you can count on Forrest for professional air conditioning service when you need it most.

Is your AC blowing warm air? Contact Forrest Air today to schedule an inspection or AC repair.