Intro
If your air conditioner is running but your home still feels warm, you’re not alone. This is one of the most common HVAC issues homeowners face in the Rio Grande Valley, especially during extreme summer heat.
Homes across Mission, McAllen, Edinburg, Pharr, Weslaco, and surrounding RGV cities rely heavily on their cooling systems for most of the year. In this Expert Tips guide, we’ll explain why AC units blow warm air, what you can safely check, and when it’s time to call a professional HVAC repair team.
Low Refrigerant Levels or a Refrigerant Leak
One of the top reasons an AC blows warm air is low refrigerant levels. Refrigerant is what absorbs heat from inside your home. When levels drop—often due to leaks—the system can’t cool effectively.
Common signs include:
- AC running constantly but not cooling
- Warm air blowing from vents
- Ice forming on refrigerant lines
- Hissing or bubbling sounds near the unit
Low refrigerant is not a DIY fix. It requires professional HVAC repair to locate leaks and recharge the system correctly.
Dirty Air Filters Restricting Airflow
In the RGV, dust and pollen build up fast. A clogged air filter restricts airflow, making it feel like your AC isn’t cooling—even if it’s working overtime.
You may notice:
- Weak airflow from vents
- Uneven temperatures between rooms
- AC running longer than usual
Regular maintenance and professional HVAC services help prevent airflow problems and reduce strain on your system.
Frozen Evaporator Coils
When airflow is restricted or refrigerant is low, the evaporator coil can freeze. When this happens, your AC may blow warm or slightly cool air but never fully cool the home.
Signs include:
- Ice buildup on the indoor unit
- Water pooling near the air handler
- Reduced airflow
Frozen coils should be inspected by a licensed HVAC technician to prevent compressor damage and costly repairs.
Thermostat or Electrical Issues
Sometimes the AC itself isn’t the problem. Faulty thermostats, miscalibration, or electrical issues can cause your system to run incorrectly.
If your AC turns on but doesn’t cool properly, the issue may involve your thermostat system, the HVAC electrical components, or even underlying electrical repair needs that affect system performance.
Your AC Unit Is Undersized or Aging
Many older RGV homes have AC systems that weren’t designed for today’s extreme heat or square footage. An undersized or aging unit may run nonstop and still struggle to cool.
Common symptoms:
- AC never reaches the set temperature
- Warm air during peak afternoon heat
- High energy bills with poor comfort
In these cases, a professional evaluation from an HVAC repair team can determine whether HVAC services or system replacement is the best long-term solution.
How to Troubleshoot Warm Air Before Calling an HVAC Pro
- Check the Thermostat Settings
Make sure your thermostat is set to “cool” and the temperature is set lower than the room temperature. If the system still blows warm air, you may need professional HVAC repair. - Replace the Air Filter
If the filter is dirty, replace it and monitor airflow. Persistent issues may require deeper HVAC services. - Inspect the Outdoor Unit
Ensure the outdoor condenser is free of debris and has proper airflow. If the unit runs but doesn’t cool, contact a licensed HVAC technician. - Watch for Ice or Water
Ice on lines or water near the unit is a sign of airflow or refrigerant problems and requires immediate HVAC repair.
When Warm Air Becomes an Emergency
Call for service right away if you notice:
- AC blowing hot air during extreme heat
- Ice forming repeatedly on the unit’
- AC shutting off unexpectedly
- Burning or electrical smells
- No airflow from vents
In RGV summers, delayed service can quickly turn into a health and safety concern. These symptoms require urgent HVAC repair from a qualified HVAC repair team.
FAQ: Bubbling Toilets & Gurgling Drains in the RGV
Is it normal for AC to blow warm air sometimes?
No. While brief temperature changes can happen, consistent warm air usually indicates an issue that needs professional HVAC services.
Can dirty filters really cause warm air?
Yes. Restricted airflow can cause coils to freeze or overheat, leading to poor cooling and the need for HVAC repair.
Do older AC systems struggle more in RGV heat?
Absolutely. Many older systems are undersized for today’s temperatures and often need upgraded HVAC services or replacement.
Should I turn off my AC if it’s blowing warm air?
Yes. Turning it off can prevent further damage until a licensed HVAC technician inspects the system.
