Why is my AC Freezing Up? Here’s What’s Really Going On

A frozen AC unit is a dysfunctional AC unit. If you want to avoid higher energy bills, equipment malfunctions, and painful repair costs, it’s important to find a solution sooner than later. Here’s what you need to know about freezing air conditioners and how to prevent them with AC maintenance services. 

What “Freezing Up” Really Means

If your air conditioner looks more like an icebox than a cooling system, it’s not because it’s working too well. When an AC unit “freezes up,” it means ice has formed on the evaporator coil due to insufficient airflow. That frozen buildup can stop your system from cooling effectively and eventually lead to damage if left untreated. Think of it like a traffic jam inside your system: everything slows down, and nothing can move the way it’s supposed to.

Possible Causes of a Frozen AC

In most cases, a frozen AC isn’t caused by a major malfunction, it’s something small that snowballs into a big issue. The most common culprit is a clogged air filter. When airflow is restricted, the system can’t absorb enough warm air to keep the refrigerant balanced. That lack of airflow causes condensation to freeze on the coils instead of evaporating, leading to ice buildup. Other airflow issues, such as closed vents, ductwork problems, or a failing blower fan can trigger the same freezing cycle. 

If you notice ice forming, resist the urge to chip away at it or crank the thermostat lower. That can do more harm than good. Instead, turn off your system and switch the fan setting to “On” to help the ice thaw gradually. Then, call in a pro to get to the root of the issue before it comes back again.

Humidity and the Colorado Twist

In Colorado’s dry climate, humidity might not seem like a factor, but it still plays a role. After afternoon thunderstorms, humidity can spike and that extra moisture in the air can collect on your already-cold coils and freeze faster than usual. Combine that with poor airflow, and your system is in for some serious stress.

Why The Ice Keeps Coming Back - and When To Call for Help

If your AC keeps freezing up, chances are the root issue hasn’t been fully addressed. It could be as simple as restricted airflow, or it could be a problem that needs a professional’s help (such as low refrigerant levels, a miscalibrated thermostat, or an aging blower motor.) These issues can trigger a recurring freeze-thaw cycle that puts strain on your system and your comfort.

In some cases, swapping out a dirty air filter and giving the system time to thaw may do the trick. But if the ice keeps coming back or your system struggles to cool even after a reset, it’s time to bring in a professional.

At A Plus Heating & AC, we help homeowners across Northern Colorado stay cool and comfortable with expert AC repair and maintenance. If your system is freezing up, give us a call or book a service online. We’ll pinpoint the cause, walk you through your options, and get your AC running smoothly again, no ice required.