By: Patricia Cermignano

Have you ever wondered how an air conditioning unit can freeze on a hot summer day? There are, in fact, several potential causes of this issue:

  • Poor Air Flow
  • Dirty Coils
  • Low Refrigerant Levels
  • Mechanical Failures
  • Insufficient Outdoor Temperature

Poor Airflow

If an air conditioning unit is not getting enough air, then the lack of heat being pulled from the warm air in a home can cause the condensation on the coils to turn into ice. It is important, therefore, to change the air filters of an air conditioning system monthly (or quarterly depending on the air filter size) and to check that there are no blocked ducts or air vents which could be causing the insufficient airflow.

Dirty Coils

A layer of dirt on top of the coils can prevent the coils from absorbing any amount water at a quick enough rate, which can cause the air conditioning unit to freeze.

Low Refrigerant Levels

When refrigerant levels are low, there is a drop in pressure in the evaporator coils. This allows for moisture in the air to accumulate and freeze on the coil. Typically, when an air conditioning system is low on refrigerant, there is a leak somewhere in the system.

Mechanical Failures

A pinched or broken refrigerant line, a damaged or broken blower fan or a clogged air filter are all examples of common mechanical failures that can cause an air conditioning unit to freeze.

Insufficient Outdoor Temperatures

Air conditioning units are only intended to run when the outside temperature is above 62°. If an air conditioner is running in temperatures below this level, the pressure inside the air conditioning unit can drop and cause the unit to freeze.


If your air conditioning unit freezes this summer, please call our office at 610-642-6323 to schedule an appointment for a technician to come and diagnose the issue.