Why Is My AC Freezing Up?

Icicles on an air conditioner in texas.

It can be disconcerting if you happen to see ice build up on your air conditioning unit in your Austin home. Why is that happening? 

There can be several causes to this air conditioning freeze-up. Our AiRCO Heating and Cooling professionals come across this often. Here are the most likely culprits and what you should do about them.

Refrigerant Levels Are Too Low

Air conditioners use refrigerant or Freon™ (the brand name) to cool your STATE home. Within the air conditioner unit itself, there is a certain level of pressure that allows the refrigerant to expand in order to function properly. 

If the refrigerant levels drop too low and the pressure remains the same, the refrigerant is forced to expand more than needed to fill the space. The higher the expansion, the colder the system becomes. This means that the air conditioner’s evaporator coil temperature gets too cold, attracting and freezing the warm moisture in the surrounding air.

Inadequate Airflow

An air conditioner requires adequate airflow through and around the system to keep it operating at its peak performance. If there is inadequate airflow, the level of heat circulating around the air conditioner will be too low, and it will cause the system to freeze. Airflow problems may come from dirty air filters, blocked air vents, clogged duct areas, or closed dampers.

If you have a split system air conditioner, there may be a problem with the way the inside air is being drawn through the system and over the evaporator coils. Since an air conditioner is designed to remove heat, and not add cooler air, the heat is required to keep the coils from freezing up.

Dirty Air Conditioner Coils

It’s natural that dirt, dust, and grime will accumulate on just about anything in your home over time, and air conditioner coils are no exception. If coils are dirty, that grime can prevent the air conditioning system from absorbing and releasing the moisture quickly enough. As a thin layer of frost builds up, it begins to block airflow even more so, which continues into a vicious cycle that results in a frozen air conditioning system.

Broken Mechanical Components

A properly functioning air conditioning unit requires a delicate balance of air exchange, pressure, and air density. The blower fan inside the unit plays a big role in making sure the heat gets taken out of your home and the cooler air is released inside your home. If this fan malfunctions, the air conditioning system can get out of whack quickly, which can cause an excess of condensation that leads to freezing-up problems.

In addition, refrigerant line damage or leaks, clogged filters, or dirty components can also throw off that delicate balance as well, causing a frozen air conditioner or other problems.

First Steps to Take to Address a Frozen Air Conditioner

Before you bring in the professionals, you can try a few troubleshooting steps yourself. First, turn off your air conditioning system. If frost and ice are building up, they will continue doing so until the root cause is found and fixed.

One of the easiest things to do is to change your air filter. A dirty or blocked filter can restrict the airflow, cause freeze-ups, and, according to the US Department of Energy, waste 5 to 15 percent of your energy. 

You can also check your evaporator coil and clean it off once your system is defrosted. If you are comfortable checking your ductwork and registers for blockages, this is another common cause of freeze-up.

If these solutions do not resolve the problem, you may want to bring in one of our professionals to check the refrigerant levels, inspect the mechanical components of your air conditioner, or perform a more thorough cleaning and repair of your system.

Call in Our Professionals

If you are facing a frozen air conditioner, contact our trained professionals at AiRCO Heating and Cooling in Austin, TX, for help. Call 512.537.1234 or request service online today.

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