Fort Collins Heating & Air Conditioning Blog


AC Freezing Fort Collins CO

Summer is the season when your air conditioning (AC) unit works overtime to keep your home cool and comfortable. But what happens when your AC, instead of keeping things cool, freezes up? It may seem counterintuitive, but an AC freezing in the summer is a common issue. Let’s dive into the reasons behind this phenomenon and what you can do to prevent and fix it.

Understanding the Basics

Before we explore the causes of a freezing AC, it’s important to understand the basic operation of an air conditioning system. Your AC works by absorbing the warm air from your home, cooling it down through the evaporator coil filled with refrigerant, and then circulating the cool air back into your living spaces. This cycle relies on a delicate balance of temperature, airflow, and refrigerant levels.

Common Reasons Your AC Freezes Up

1. Restricted Airflow

One of the most common causes of a freezing AC is restricted airflow. When the air cannot flow freely over the evaporator coil, the temperature of the coil drops significantly, leading to the formation of ice. Restricted airflow can be caused by:

  • Dirty Air Filters: Air filters trap dust, dirt, and other particles. When they become clogged, they restrict the airflow, leading to freezing. It’s crucial to check and replace your air filters regularly.
  • Blocked Vents: Ensure that the vents in your home are not blocked by furniture, drapes, or other objects. Blocked vents can reduce airflow and cause your AC to freeze.
  • Closed Dampers: Some HVAC systems have dampers that control airflow to different parts of the house. Closed or partially closed dampers can restrict airflow, causing the evaporator coil to freeze.

2. Low Refrigerant Levels

Refrigerant is the lifeblood of your AC system. It absorbs heat from the air and cools it down. If the refrigerant levels are low, it can cause a frozen evaporator coil. Low refrigerant levels can be due to:

  • Leaks: Refrigerant leaks are a common issue in older units or units that haven’t been maintained properly. If you suspect a refrigerant leak, it’s essential to contact one of our professional technicians to locate and repair the leak and recharge the refrigerant.
  • Improper Installation: If your AC unit was not installed correctly, it could have incorrect refrigerant levels from the start. This is why it’s crucial to hire experienced professionals for installation.

3. Thermostat Issues

The thermostat is the control center of your AC system. If it’s not functioning correctly, it can cause the system to run continuously or not run enough, leading to freezing. Common thermostat issues include:

  • Faulty Thermostat: A malfunctioning thermostat can cause the AC to overcool the house, leading to a drop in temperature around the evaporator coil and eventual freezing.
  • Improper Thermostat Placement: If the thermostat is placed in a location that is too hot or too cold, it can cause the AC to run improperly. Ensure that your thermostat is installed in a central location away from direct sunlight or heat sources.

4. Dirty Coils

Both the evaporator and condenser coils need to be clean for the AC to function efficiently. Dirty coils can disrupt the heat exchange process, causing the evaporator coil to become too cold and freeze. Regular maintenance and cleaning of the coils can prevent this issue.

5. Fan Problems

The fan in your AC unit is responsible for blowing air over the evaporator coil and throughout your home. If the fan is not working correctly, it can reduce airflow, leading to a frozen coil. Fan problems can include:

  • Faulty Fan Motor: A malfunctioning motor can cause the fan to run slowly or not at all.
  • Bent or Broken Blades: Damaged fan blades can reduce airflow and lead to freezing.

Preventing Your AC from Freezing

Preventing your AC from freezing up involves regular maintenance and a few proactive steps:

  1. Regularly Replace Air Filters: Check your air filters every month and replace them if they are dirty. Clean filters ensure proper airflow and prevent freezing.
  2. Clean the Coils: Schedule annual maintenance to have the coils cleaned. This will keep your system running efficiently and prevent ice buildup.
  3. Check Refrigerant Levels: Have a professional check and maintain the correct refrigerant levels in your system. If you suspect a leak, address it immediately.
  4. Inspect the Thermostat: Ensure your thermostat is functioning correctly and is placed in an optimal location.
  5. Maintain Clear Vents: Make sure all vents are unobstructed and allow for proper air flow throughout your home.
  6. Routine Maintenance: Regular professional maintenance can catch potential issues early and help save you from costly repairs.

What to Do if Your AC System Freezes

If you notice your AC has frozen, follow these steps:

  1. Turn Off the AC: Switch off the AC to allow the ice to melt. Running the system with ice buildup can cause damage to the compressor and other components.
  2. Check the Air Filter: Replace or clean your air filters on a regular basis.
  3. Inspect the Coils and Fan: If you’re comfortable doing so, inspect the coils and fan for dirt or damage. Otherwise, contact one of our professionals.
  4. Call Our Experienced Technicians: If the problem persists, it’s time to call one of our professional HVAC technicians. We can diagnose and fix the issue, ensuring your system operates efficiently.

A freezing AC in the middle of summer can be a frustrating problem, but understanding the common causes and preventive measures can help you address it quickly. Regular maintenance, proper airflow, and keeping an eye on refrigerant levels and thermostat functionality are key to keeping your AC running smoothly. If you encounter persistent issues, don’t hesitate to reach out to Fort Collins Heating & Air for expert assistance. We are here to ensure your home remains cool and comfortable during the hot summer days.


Fort Collins Heating & Air Conditioning Blog