When your air conditioner is running, the last thing you expect to find is a buildup of ice not just inside your home, but somewhere you rarely visit – inside your attic. But that’s where most people keep their AC air handlers, and air handlers can and do freeze, even on the hottest days of summer.

What Is an Air Handler?

An air handler is the indoor component of your central air conditioning system. It houses the blower fan and the evaporator coil – co-responsible for circulating cooled air throughout your home. When everything is working properly, the air handler quietly delivers consistent comfort. But when it freezes up, your AC can’t cool efficiently, and maybe not at all.

Common Reasons an Air Handler Freezes

1. Restricted Airflow
When not enough warm air moves over the evaporator coil, condensation builds up and freezes. Over time, that ice spreads, reducing system efficiency and potentially damaging it.

And what causes poor airflow in the first place? A dirty air filter, a closed or blocked vents, obstructed or dirty return grills, and collapsed ductwork.

2. Low Refrigerant Levels
When your AC system is low on refrigerant—usually due to a leak—the pressure in the system drops. This causes the temperature of the evaporator coil to fall below freezing, thus turning condensation into ice. Low refrigerant is a serious problem that should be rectified by one of our HVAC technicians.

3. Dirty Evaporator Coil
If the coil inside the air handler is covered in dust or grime, it can’t absorb heat properly. This leads to the same cooling imbalance that causes freezing. Dirty coils are typically the result of infrequent maintenance.

4. Thermostat or Blower Issues
Faulty thermostats or malfunctioning blower fans can disrupt the cooling cycle. If the blower isn’t pushing enough air across the coil, the system is more likely to freeze.

How to Prevent Your Air Handler from Freezing

The smart play is to prevent your air handler from freezing in the first place. Here are four convenient and helpful ways you can help your own cause.

1. Change Your Air Filter Regularly
A clean filter is your first defense against restricted airflow. Replace it every 1–3 months—or more often if you have pets or family members with allergy or asthma conditions.

2. Keep Vents and Returns Clear
Make sure all supply and return vents are open and unblocked. Avoid placing furniture or rugs in front of vents, and vacuum vents periodically to remove dust.

3. Schedule Routine HVAC Maintenance
Professional tune-ups help catch early signs of trouble, like dirty coils or low refrigerant levels. Regular maintenance keeps your system running efficiently and prevents most freezing issues before they start.

4. Watch for Warning Signs
If your AC starts blowing warm air, making strange noises, or running continuously, it might be on the verge of freezing. Shut it off and call a professional before it worsens. Or climb up into your attic to see if freezing has already occurred.

Don’t Let Ice Burn a Hole in Your Budget

A frozen air handler isn’t just inconvenient—it can cause long-term damage to your AC system if ignored. But with regular upkeep and other assistance from C&D Cooling & Heating. it’s easy to avoid.

For starters, call us to schedule an AC tune-up and inspection if it’s been a year or longer since your last one, or if you think your system isn’t behaving up to par.