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  • Writer's pictureRobert Douglas

The Chilling Truth: Why Air Conditioning Units Freeze Up During Summer

Is your A/C unit leaving you hot during the summer?

As the scorching summer heat sets in, our air conditioning units become our best friends, providing cool and refreshing relief. However, there may be times when your AC unit unexpectedly freezes up, leaving you puzzled and without proper cooling. In this blog post, we will delve into the reasons behind this phenomenon and provide you with insights on how to prevent it from happening.

Frozen A/C
Frozen Evaporator Coil

  • Insufficient Airflow: One of the primary culprits behind frozen AC units is insufficient airflow. When the airflow is restricted, it causes the evaporator coil to become colder than it should be, eventually resulting in ice formation. Several factors contribute to restricted airflow, including:

    • Dirty air filters: Clogged filters impede the passage of air, causing the coil to freeze up.

    • Blocked vents: Furniture, curtains, or other obstructions near the vents can restrict the airflow.

    • Dirty Coil: Dust, dirt, and debris on the coil act as an insulating barrier, preventing proper heat exchange between the refrigerant and the air. As a result, the coil gets colder than it should, causing moisture from the air to freeze on its surface.

    • Closed or blocked return vents: Ensure that all return vents are open and unobstructed.


  • Low Refrigerant Levels: Refrigerant is a crucial component that allows your air conditioning system to cool the air effectively. If your unit has a refrigerant leak, the refrigerant levels drop, disrupting the cooling process. As a result, the evaporator coil can get excessively cold, leading to ice buildup. If you suspect a refrigerant leak, it's essential to contact a professional HVAC technician to identify and repair the issue.

  • Malfunctioning Components: Various mechanical issues can contribute to an AC unit freezing up. Faulty components such as thermostats, fans, or blower motors can disrupt the normal operation of the system, leading to temperature imbalances and ultimately causing the evaporator coil to freeze. Regular maintenance and prompt repairs can help identify and address these problems before they worsen.

  • Humidity Levels: Humidity plays a significant role in the freezing of air conditioning units. When the humidity is high, moisture can accumulate on the evaporator coil. As the coil temperature drops, the moisture freezes, creating a layer of ice. To combat this issue, consider using a dehumidifier or setting your thermostat to a slightly higher temperature, allowing for better humidity control.

Preventive Measures: To keep your air conditioning unit running smoothly throughout the summer and prevent freezing, follow these preventive measures:

  • Regular maintenance: Schedule professional maintenance to ensure proper airflow, refrigerant levels, and overall system functionality.

  • Change air filters: Replace your air filters regularly to prevent blockages and maintain optimal airflow.

  • Keep vents unobstructed: Ensure that furniture, curtains, or other objects are not blocking the vents.

  • Check thermostat settings: Ensure that your thermostat is set to an appropriate temperature and that it is functioning correctly.

  • Monitor humidity levels: Use a dehumidifier if necessary to maintain optimal humidity levels in your home.

Understanding the reasons behind air conditioning unit freezing during the summer can help you take proactive measures to prevent this issue. Regular maintenance, proper airflow, and humidity control are key factors in keeping your AC unit running efficiently. Should you encounter a frozen unit, it's crucial to contact a professional HVAC technician like Florida's Coolest A/C to diagnose and resolve the underlying problem. Stay cool and comfortable all summer long by giving your AC unit the care it deserves.

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