It’s a common occurrence: Your AC system isn’t cooling your home, blowing warm air, or doing nothing at all. You scope out the situation, only to find your coils or refrigerant lines encased in ice. It’s pushing 100 degrees outside – how is it possible it’s frozen? An AC unit freezing up in the summer is a common issue. Fortunately, you can restore it to proper operation by getting to the heart of what caused the malfunction.
Airflow, system pressure, and temperature play major roles in the performance of your air conditioner. When issues occur that disrupt this balance, key components can freeze. Our air conditioning contractors see the following top culprits for this:
Clogged air filter
Dirty home air filters don’t allow sufficient airflow for your system to perform effectively. This is the most common reason for HVAC system repair – and it’s preventable. We recommend checking your air filter first. If it’s caked with dust and dirt, replace it – especially if it’s been more than 3 months since you last changed it. Turn your system off until it defrosts. Then your system should return to normal operation.
Fan or blower motor malfunction
Constant airflow is essential to prevent humidity from settling (and freezing) on coils. When electrical or mechanical issues lead to fan or blower malfunction, the lack of airflow can quickly lead to a frozen AC unit. To identify and address this situation, you’ll need the help of a pro.
Vent or ductwork blockages
Closing or blocking supply or return ducts with furniture or blockages in ducts can reduce airflow and cause a frozen unit. Clear all return ducts and close no more than 2-3 supply ducts, ensuring free flow of air.
Low refrigerant levels impact pressure in the system, causing coil temperatures to plummet and nearby water vapor to freeze, forming frost and eventually ice. Finding the leak and restoring refrigerant to proper levels is essential to permanently addressing this issue. As with fan/blower malfunction, professional assistance is necessary to manage refrigerant issues. Keep in mind, however, for some older systems wearing in dated components may make eliminating leaks difficult. Due to the cost of refrigerant, HVAC system replacement may be the most cost-effective solution.
Clogged drain lines cause water to back up, creating a high moisture environment that makes your evaporator coil more susceptible to freezing. A wet/dry vac can help you quickly dislodge algae and debris causing clogs. Once your system thaws, it should be back in action.
Less than optimal operating temperatures can lead to frozen components. When evenings are cooler than expected (near or below 60 degrees), there may not be enough heat to absorb during the cooling cycle.