Summer in Aurora, IL, means relying on your air conditioner to keep your home comfortable through long stretches of heat and humidity. So it can be genuinely puzzling when, after running for a while, the system stops cooling effectively, and a closer look reveals ice forming somewhere on the unit.
Ice on an AC unit is not necessarily a sign of a major problem, but it should not be ignored either. Left unaddressed, it can lead to more significant system damage over time. Here is what typically causes this issue and what it means for your cooling system.
Blocked Airflow Through the Unit
Your air conditioner’s evaporator coil relies on consistent airflow moving across it to function properly. When airflow is restricted, the coil can drop below freezing, and ice begins to form, which further blocks airflow and prevents the system from cooling your home.
A dirty air filter is one common cause of this restricted airflow, and furniture or other objects blocking return vents can have the same effect. Ensuring clear airflow around the system and allowing any existing ice to thaw fully before running the unit again are reasonable first steps. If the problem returns after addressing these obvious airflow obstructions, an underlying issue likely needs professional diagnosis.
A Dirty Evaporator Coil
An evaporator coil accumulates dirt and grime over time, and once enough buildup has occurred, the coil can freeze on its own, independent of any external airflow blockage. This is why regular AC maintenance, including professional coil cleaning, is a standard part of keeping a cooling system running reliably.
Even after a frozen coil has been thawed, the system will continue to underperform until the coil itself has been properly cleaned. This is not a task to attempt independently. Evaporator coils are delicate components that are easy to damage without the right tools and technique, which is why professional AC repair service is the appropriate response.
A Clogged Air Filter
A heavily soiled air filter is one of the more common and straightforward causes of ice forming on an AC unit. When dust and debris accumulate to the point of significantly restricting airflow, the system is prone to freezing up rather than cooling effectively.
Checking the filter’s condition, a badly clogged filter often appears visibly dark rather than its original color, which is a reasonable homeowner task, and replacement is typically straightforward for anyone comfortable doing so. If you would rather leave it to a professional, our team is happy to handle filter replacement as part of a broader system check.
Low Refrigerant Levels
Cooling performance that has gradually worsened over several weeks, to the point where the system no longer cools the home effectively, regardless of runtime, is a strong indicator of low refrigerant, most often caused by a leak somewhere in the system.
When refrigerant levels drop, system pressure decreases, causing the evaporator coil to become too cold and eventually ice over. This is a situation that requires professional attention, since locating and repairing a refrigerant leak involves specialized tools and licensing. An AC installation and replacement specialist can also advise on repair versus replacement if the leak affects an older system.
Outdoor Temperatures Too Low for Operation
Running an air conditioner when outdoor temperatures fall below approximately 62 degrees is outside the conditions the system was designed to handle, and doing so can cause it to freeze and stop working properly. This is a straightforward issue to correct: shutting the system off and allowing it to thaw fully resolves the immediate problem, and avoiding operation during unusually cool stretches prevents it from recurring.
Mechanical Problems Within the System
When an air conditioner freezes without an obvious explanation, an underlying mechanical issue, such as a failing fan, damaged wiring, or a faulty valve, may be responsible. These repairs can range in cost depending on the specific component involved.
For units 15 years or older, weighing the cost of an involved mechanical repair against the value of a full system replacement is often worth a conversation with a professional, particularly if the unit has required repeated service calls.
Andersen Thaws Out Aurora’s Cooling Problems
Ice on an air conditioner is a signal worth taking seriously, whether the underlying cause is a simple filter issue or something requiring more involved repair. Getting to the actual source protects your system from further damage and restores the reliable cooling your home needs through an Aurora summer.
If the ice on your unit refuses to thaw or if your system is leaking water, our team at Andersen Plumbing, Heating, and AC Repair is ready to help. Contact our team today to schedule service and get your AC running reliably again.