Article Updated - April 2025
Serving the Burbank Area Since 1990 - Your Trusted Local HVAC Experts
California heat can be relentless, and the last thing you want is to hear your air conditioner humming away without any cool air making its way into your home. At Kilowatt Heating, Air Conditioning & Electric, serving the Burbank area and surrounding communities since 1990, we understand the frustration and discomfort this can cause. One of the most common reasons for this issue is a frozen evaporator coil inside your AC unit.
You might be thinking, "My AC is running, so why isn't it cooling?" The answer lies in the fundamental way your air conditioner works. Your AC unit circulates refrigerant through a closed system. Inside the indoor unit (the air handler), this refrigerant passes through the evaporator coil. As warm air from your home is blown across this cold coil, the refrigerant absorbs the heat, cooling the air before it's circulated back into your living spaces.
The Role of Condensation and Why It Can Lead to Freezing
A natural byproduct of this cooling process is condensation. Just like a cold glass of water on a humid day, the cold evaporator coil causes moisture in the warm air to condense into water. A properly functioning AC system has a drainage system to handle this condensate, sometimes producing as much as 20 gallons of water per day!
However, when the airflow across the evaporator coil is restricted, the coil becomes excessively cold. This super-chilled coil can then cause the collected condensation to freeze. As more and more condensation freezes, it forms a solid block of ice around the coil, effectively preventing warm air from passing over it and thus blocking the flow of cool air into your home.
Why is Airflow Blocked? Common Causes of AC Freeze-Up
Understanding the reasons behind restricted airflow is crucial for preventing future issues. Here are some of the most common culprits:
Dirty or Clogged Air Filter: This is the most frequent cause of AC freeze-up. A dirty air filter restricts the amount of warm air flowing over the evaporator coil. This lack of airflow causes the coil to get too cold, leading to ice formation.
Blocked Return or Supply Vents: Furniture, rugs, or even closed vents can obstruct the flow of air into or out of your AC system. This imbalance in airflow can lead to the same super-cooling effect on the evaporator coil.
Dirty Evaporator Coil: Over time, dust and debris can accumulate on the evaporator coil itself, acting as an insulator and hindering proper heat exchange. This can also lead to the coil becoming too cold and freezing.
Refrigerant Leaks: While less common, a refrigerant leak can lower the pressure in the system, causing the evaporator coil to become excessively cold and freeze. This is a more serious issue that requires professional attention.
Faulty Blower Motor: The blower motor is responsible for circulating air across the evaporator coil. If the blower motor is not functioning correctly or is running at a reduced speed, it can lead to insufficient airflow and subsequent freezing.
Ductwork Issues: Damaged or improperly designed ductwork can also restrict airflow throughout your system.
Help! My AC is Frozen - Here's What You Should Do:
If you've noticed your AC running but no cool air is coming out, and you suspect a frozen coil, here's a step-by-step guide:
Turn Off Your Air Conditioner Immediately: This is the most important first step. Continuing to run the AC with a frozen coil can cause further damage to the system. Turn the thermostat to the "Off" position or "Fan Only" mode. The "Fan Only" mode can sometimes help speed up the thawing process by circulating room temperature air over the coil.
Do NOT Try to Chip Away the Ice: Attempting to manually remove the ice can damage the delicate fins on the evaporator coil, leading to costly repairs.
Change or Clean Your Air Filter (If You Haven't Recently): As mentioned earlier, a dirty air filter is a primary culprit. Replacing a dirty filter with a clean one can help prevent future freeze-ups and improve overall system performance.
Ensure Vents Are Open and Unobstructed: Check all supply and return vents in your home to make sure they are fully open and not blocked by furniture, curtains, or other objects.
Clear the Outdoor Unit: Make sure the outdoor condenser unit is free from any obstructions like weeds, vines, leaves, or debris. Good airflow around the outdoor unit is also crucial for proper AC operation.
Wait for the Ice to Melt: This can take several hours, typically between 1 to 24 hours, depending on the severity of the ice buildup and the ambient temperature.
Monitor for Water Leaks: As the ice melts, there will be a significant amount of water. Ensure the condensate drain line is not clogged and that water is draining properly. If you notice excessive water pooling, it could indicate a drainage issue that needs professional attention.
Turn the AC Back On (Carefully): Once you believe the coil has completely thawed, turn your AC back on and monitor its performance. If cool air starts flowing again, it's a good sign. However, if the issue recurs quickly, it indicates an underlying problem that needs professional diagnosis and repair.
Call the Experts at Kilowatt Heating, Air Conditioning & Electric for Service: If the problem persists, or if you suspect a more serious issue like a refrigerant leak or a faulty component, don't hesitate to call us at (818) 446-2099 for prompt and reliable air conditioning service in the Burbank area. Our experienced technicians can accurately diagnose the cause of the freeze-up and perform the necessary repairs to get your system running efficiently again.
Preventing Future AC Freeze-Ups: Proactive Maintenance is Key
While dealing with a frozen AC can be frustrating, the good news is that many of the underlying causes are preventable with regular maintenance:
Regular Air Filter Changes: As emphasized before, this is the simplest and most effective way to maintain good airflow. Aim to change or clean your filter every 1-3 months, or more frequently if you have pets or allergies.
Annual HVAC Tune-Ups: Schedule professional AC maintenance for your HVAC system at least once a year, preferably before the start of the cooling season. Our technicians will thoroughly inspect and clean your system, check refrigerant levels, ensure proper airflow, and identify any potential issues before they escalate.
Keep Indoor and Outdoor Units Clear: Regularly inspect and clear any obstructions around both your indoor air handler and your outdoor condenser unit. Trim vegetation and remove any debris that could impede airflow.
Ensure Proper Ventilation: Avoid blocking vents with furniture and ensure that all rooms have adequate airflow.
We're Here to Help You Stay Cool in Burbank
Dealing with an air conditioner that's running but not cooling is never a pleasant experience, especially during the hottest months in Burbank and the greater Los Angeles area. At Kilowatt Heating, Air Conditioning & Electric, we're committed to providing reliable and efficient air conditioning repair and maintenance services to keep your home comfortable.
If you're experiencing an AC freeze-up or any other cooling issues, don't hesitate to contact our friendly team at (818) 446-2099. We're here to help you get back to enjoying a cool and comfortable home. We also offer flexible financing options to make necessary repairs and upgrades more accessible.
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