An air conditioner covered in ice sounds backward in the middle of a hot Pennsylvania July, but it is one of the most common summer service calls Shoemaker Heating and Cooling LLC receives from homeowners in Morgantown, Caernarvon Township, and the Twin Valley area of southern Berks County. Call (610) 671-3595 if you are seeing frost or ice on your system right now.
Morgantown sits at the convergence of the Pennsylvania Turnpike and Route 176, and the area has grown quickly in recent years with new residential development alongside its older farmhouse and borough housing stock. Both older systems with aging refrigerant lines and newer systems installed without proper airflow balancing can develop freezing problems during peak summer runtime.
What Causes an AC Unit to Freeze Up
Restricted airflow is the leading cause. When less warm household air passes across the evaporator coil than the system is designed for, the coil surface temperature can drop below freezing, and moisture in the air condenses and freezes directly onto the coil. A dirty air filter is the most frequent culprit, followed by closed or blocked supply vents, undersized return ductwork, and a failing blower motor. Routine HVAC maintenance catches most of these issues before they cause a freeze up.
Low refrigerant charge is the second leading cause. A system low on refrigerant runs at an abnormally low pressure and temperature inside the coil, which can cause ice to form even with normal airflow. Refrigerant does not deplete on its own in a properly sealed system, so any low charge points to a leak that needs to be located and repaired, not simply topped off.
Less common causes include a dirty evaporator coil that is already partially blocked with dust and debris, a stuck or failing blower motor that is not moving enough air, and outdoor temperatures that drop unusually low overnight while the system continues running on a schedule designed for daytime heat.
What to Do If Your AC Freezes Up
- Turn the system off completely at the thermostat and switch the fan setting to Auto.
- Do not attempt to chip or scrape ice off the coil or refrigerant lines. This can puncture the coil and turn a simple repair into an expensive one.
- Allow several hours, often overnight, for the ice to fully melt on its own.
- Check and replace the air filter once the system is off, since a dirty filter is the most common cause.
- Place towels around the indoor unit before the ice melts, since a significant amount of water will drain as it thaws.
Per ENERGY STAR guidance, homeowners should check their air filter monthly during heavy summer use, since restricted airflow is behind a large share of the freeze up and no cool service calls HVAC contractors see each July.
Why This Is More Common in Morgantown and Southern Berks County in Summer
Homes throughout Caernarvon Township and the Twin Valley area run their AC systems nearly continuously through July, and older homes with retrofitted or partially undersized ductwork are more prone to airflow restrictions that lead to icing. New construction in the area around the Morgantown Turnpike interchange sometimes has ductwork sized for standard loads that does not account for the additional strain of continuous summer operation, which can also contribute to freeze up issues if not addressed during installation.
If your system has frozen and you need a same day diagnosis, Shoemaker offers emergency HVAC service throughout Morgantown, Elverson, and the surrounding southern Berks County communities as part of our expanded service area covering Chester and Berks Counties.
Learn more about diagnostic and repair options on our air conditioning services page.
Frequently Asked Questions
AC Freezing Up in Morgantown, PA
The two leading causes are restricted airflow, usually from a dirty filter, closed vents, or a failing blower motor, and low refrigerant charge from a leak. Both cause the evaporator coil temperature to drop below freezing, forming ice that blocks normal cooling operation.
No. Running a frozen system can flood the compressor with liquid refrigerant, which can cause permanent compressor damage. Turn the system off, set the thermostat fan to Auto, and allow several hours for the ice to fully melt before restarting or scheduling service.
No. Chipping or scraping ice off the evaporator coil or refrigerant lines can puncture the coil or lines, turning a filter or refrigerant issue into an expensive repair. Let the ice thaw naturally with the system powered off.
Yes, it is one of the most common causes. A clogged filter restricts the volume of warm household air moving across the evaporator coil. Without enough warm air passing over it, the coil temperature drops below freezing and moisture in the air begins to form ice on the coil surface.
Yes. Shoemaker Heating and Cooling provides AC repair and diagnostic service throughout Morgantown, Caernarvon Township, Elverson, and the Twin Valley area of southern Berks County, along with all of Chester County. Call (610) 671-3595 to schedule.