Does Your AC Unit Blow Warm Air? 7 Possible Causes

A working air conditioner is necessary for your home to be cool and comfortable. If the air flowing from your air conditioner vents is warm rather than cool, your AC system has a problem. Check out the possible causes of an AC unit blowing warm air below.

1. Closed Return Vents

Many people close vent grilles over winter and forget to reopen them when it gets warm. Walk around the house and ensure that all returns and registers are open to facilitate airflow. The vents should also be free of obstructions like furniture, children's toys, and debris. 

2. Incorrectly Set Thermostat

Thermostat issues sometimes interfere with AC system functions. For instance, an improperly-wired thermostat causes various problems, including an air conditioner that blows warm air. Expert installation is vital when buying a new AC unit in order to prevent wiring issues.

Verify that your thermostat isn't set to the heating mode, especially if your children often tamper with appliances. When it's hot, the thermostat should stay in the 'cool' setting, and the temperature shouldn't be too high. Sometimes the thermostat only needs a change of batteries to resume normal function.

3. Refrigerant Leak

Your air conditioner has a fluid called refrigerant that absorbs heat and cools your home. If the refrigerant leaks, the AC system gradually loses its capacity to cool the air in your house. If the leak is small, you will likely only realize there is a leak once the refrigerant runs quite low.

Refrigerant leaks can be difficult to notice, but hissing noises and unusually steep energy bills typically accompany low refrigerant levels. Don't attempt to fix the leak, as refrigerants are health hazards. Instead, have an HVAC technician check your system and sort out the issue.

4. Leaking Ducts

The ductwork is responsible for channeling conditioned air throughout your home. Since ducts run through the walls and ceiling, they act as hiding places for rodents. If you have recently had a construction project, careless workers may also leave holes in the ductwork. 

Leaky ducts facilitate the escape of conditioned air from the unit, leaving your home warm and uncomfortable during the hottest months. High energy costs are another result of damaged ductwork, which is why you should have an HVAC professional fix them promptly.

5. Frozen Evaporator Coils

Evaporator coils sit in the air handler — where they absorb heat and cool your home. The condensate drain prevents water from accumulating in the evaporator coil but gets clogged over time, causing the evaporator coils to freeze. As a result, the coils cannot soak up heat, and the AC unit blows warm air. 

6. Dirty Condenser Coils

Air conditioner condenser coils are situated on the outdoor unit and allow heat transfer outside the building. Over time, these coils attract dust and debris and get clogged with twigs, leaves, and shrubs. Dirty condenser coils are less efficient at transferring heat and leave your AC system blowing unconditioned air.

Clear the area around the outdoor unit periodically and schedule regular HVAC maintenance.

7. Clogged Air Filters

The solution to an AC unit blowing warm air is commonly as simple as changing your air filters. Air filters perform the critical task of removing dust and debris from the air and protecting indoor air quality. 

Over time, pollutants build up on the air filter, creating airflow issues that strain your AC system. Energy bills also increase since the AC unit works harder to maintain indoor temperature. Change the air filters consistently, especially if you have pets. 

At Brooks Heating & Air Conditioning, we know how important a functioning AC system is to your family's comfort. Our cooling experts offer quick and personalized air conditioning services to keep you cozy year-round. Call us today for any AC system problems.