Schedule An Appointment

What Causes an Air Conditioner to Ice Up?

  • July 26, 2013

If your air conditioner is running but it is blowing hot air, check the evaporator coil at the indoor air handler for ice accumulation. If there is ice, you can usually narrow the issue down to two reasons for what causes an air conditioner to ice up. Keep reading to find out if you can troubleshoot the problem yourself, or if you need the expertise of an HVAC pro.

What causes an air conditioner to ice up?

A frozen evaporator coil can raise tempers and temperatures on a hot day. The air conditioner is turned on and working — almost. Hopefully, the issue can be resolved quickly with little fuss. But, that depends on the cause for ice accumulation.

An air conditioner needs free air circulation across the indoor evaporator coil and the outdoor condenser coil to instigate heat exchange. In addition to cooling, the evaporator coil draws moisture from indoor air, which condenses on the coil. If the coil is too cold because of a lack of air circulation, the condensation freezes, and quickly gets out of hand once it starts.

Troubleshoot the following components first:

  • A clogged air filter obstructs air circulation to the evaporator coil. It also increases energy consumption by placing more strain on the compressor and other components. Clean or replace the filter if it’s dirty.
  • You must allow the ice to melt on its own. You may help it along with a hair dryer, but do not use tools to remove the ice.
  • After the ice has completely melted, which may take several hours, turn the air conditioner on to see if it cools your home. If it does, you may have saved yourself a service call. However, if the evaporator ices up again, there is another issue in play.

Refrigerant charge must be very close to the manufacturer’s specifications for optimal cooling. If refrigerant charge is off by more than a few ounces, you may get a frozen evaporator. Refrigerant issues may only be corrected by a certified HVAC professional.

If you’re at your wits end for what causes an air conditioner to ice up, call the cooling professionals at Comfort Services.