How To Unfreeze An Air Conditioner: 5 Easy Tips To Get Your AC Working

You were shocked to spot a bit of ice forming on the outside of your air conditioning unit, and thought, “Wow! My AC is so cool, it’s actually making ice!” And yet, you feel the air in the room is warmer than usual.

As you sweat through your confusion, you notice the thermostat is telling you the air conditioner isn’t working properly. With how hot it is outside, you know you’re in trouble.

So why is your air conditioner freezing up? And what you really need to know is how to unfreeze an air conditioner and get your home comfortable again.

How To Unfreeze An Air Conditioner

The key to dealing with an air conditioner that has frozen is to take immediate action to prevent damage. Then follow these 5 steps to unfreeze an air conditioner: 

Let the AC thaw

Upon seeing that your air conditioner or parts of it are covered with ice, you might be tempted to remove it by hand. Resist that temptation! The cold coils are a series of copper, steel, or aluminum tubes but haphazardly breaking the ice off might risk damaging the refrigerant line or the fins on the coil.

The ice you see is usually just the tip of the iceberg. Much more ice has formed in the evaporator coil that is located in the ductwork of your home.

The best way to remove the ice is to let it melt on its own by turning off all power to the air conditioner and air handler or furnace that is inside your home. Turning off the power will prevent any water from the melting ice from harming electrical components with the units.

How long you need to keep it off depends on the amount of ice that has formed. Be ready with some towels or a mop in case the water will be too much for the drain pan to handle. 

Wash or replace the HVAC air filters

Probably the simplest, yet the most easily forgotten maintenance to do to a household AC is to replace the air filters. 

The air filter’s job is to trap dirt such as dust, pet dander, pollen, dust mites, and other unwanted particles to prevent them from circulating inside the ac unit. More importantly, the AC filters keep the indoor air quality of your home in good condition so your family will not be exposed to airborne allergens.

But they are not meant to last forever. Eventually, the dust and dirt particles will accumulate, build up, and hamper the airflow. That lack of air flow can cause a frozen air conditioner.

So, make it a habit to clean your air filters if you employ a reusable type or replace the disposable ones, a minimum of every three to six months.

Clean the AC unit

After defrosting the ac unit and replacing the filters with a fresh one, it is time to focus your attention on the problematic area. One probable cause of its freezing is the evaporator coils are dirty.

Since we talked about how sensitive these coils are and its surrounding components, you might want to use a soft plastic brush with nimble hands in cleaning them.

If you are unsure that you will be able to do the cleaning gently, it would be a good idea to get the help of your trusted HVAC technician to do it for you.

Optimize the airflow

If neither the AC filters nor the coils are the problem, you might want to check your vents or grates around the house.

Supply vents are where the cold air supplied by the air conditioner is blown to different rooms, while return vents are openings in which the warm air is pulled from the rooms to be processed by the AC.

If these vents are either closed on purpose or blocked accidentally, the airflow would once again be obstructed, causing the AC to freeze up.

Fix the refrigerant leak

If your AC system is low on refrigerant, it will be prone to freezing up. “How’s that?” you might ask. “Less refrigerant means less cooling, right?”

Yes and no.

While it is true that your AC will not be able to efficiently lower the temperature of your home with low refrigerant levels, the coils are still susceptible to icing. With low refrigerant, the pressure will also decrease, hence the temperature inside the ac unit will be lower leading to freezing.

Only a refrigerant leak can cause the refrigerant level of your air conditioning to drop. So this particular issue should be handed over to a professional. Only a qualified HVAC expert can locate these leaks and repair them safely.

Why Does My Air Conditioner Freeze Up?

If you notice that your air conditioner starts freezing up, it certainly needs your attention. The evaporator coils of the AC are the most susceptible to icing because it is the component where the condensation process occurs. 

The refrigerant, in its liquid state, runs through the cold coils. When the air conditioner draws in the warm air from the room, its high temperature will change the state of the refrigerant to gas. This process will remove the heat from the air and colder air gets blown back to your living space.

The problem often starts when there isn’t sufficient airflow between the AC and space it is supposed to cool. In the absence of warm air, the evaporator coils will reach an extremely low temperature and turn the humidity inside the AC to ice.

If you have multiple air conditioning units inside the premises or are often away, it might not be easy to determine if a unit is already frozen. Be attentive if the AC blows warm air, takes too long to reach the thermostat temperature, or ice formation is beginning to be visible on the evaporator coils, or in worse cases, outside the ac unit.

The basic remedies to an AC that is icing up are making sure that the airflow is not obstructed in any way, cleaning the air filters and evaporator coils, or asking the help of a certified HVAC expert. Identifying the specific causes of your frozen AC will help in preventing a similar problem  in the future.

Chances are—if your AC is working properly—you might not even notice its presence. Your “normal” temperature has become the artificial cold you have become so used to.

So, it does not take a lot for you to notice when your trusted AC starts acting weird. You feel warmer than usual even if your AC has been running all day, and it takes a while before it reaches the temperature in the thermostat that you set.

Now is a good time to pay close attention and investigate why your air conditioner freezes up.

When Your AC is Chilling the Wrong Way

Your detective work should start on how hot or cold the general temperature of the room currently is. You may employ the help of a thermometer but being acclimated to the normally cold or “comfortable” temperature is frequently enough an indicator that something is not right with your processed air.

Hence the number one sign that your AC could be freezing up is: 

Your AC is blowing warm air

There are a few things more infuriating than an air conditioner that instead of cooling you off is making you feel you are inside a sauna. Although the temperature in your home is largely dependent on your thermostat setting, it is highly unlikely that you will feel warmer instead of colder upon turning an AC on. 

When the warm air of your home is pulled in by the blower, it hits the evaporator coils and immediately boils the refrigerant inside. As the refrigerant “evaporates” or changes its state from liquid to gas, the heat is absorbed from the air.

Let’s say the temperature of your indoor air that gets drawn in is 75 degrees Fahrenheit. Since an average AC is designed to lower the temperature to 20 degrees lower in every exchange, the air that gets blown to your living space should be about 55 degrees.

This process continues several more times until the temperature matches what you set in your thermostat as your desired level.

Understanding this, if you put your hand over the blower of the AC, it should always be colder than the room temperature. If it’s warm, then you have a problem.

Ice formation is visible outside of the ac unit

If ice starts forming outside your AC unit or condensation starts dripping, it means that the freezing up of your AC is no longer contained inside the unit but spreading rapidly beyond the coils.

In the same way that a freezer with ice build-up is never good news, your AC is displaying signs that it needs proper attention and maintenance. 

The rule of thumb is that the air exchange between your home and the air conditioner should NEVER be obstructed. If the AC is signaled by the thermostat to start the cooling process, and yet there is no heat from the warm air that gets drawn in, the evaporator coils would be left to be too cold.

Humidity or excess moisture from inside the machine would form condensation on the cold coils but will turn to ice in the absence of heat. If and when the AC is turned off, a significant amount of water will condensate, which your drain pan will not be able to handle and thus leak outside the ac unit. 

Evaporator coils are covered with ice

It is easy to assume that since the AC is a cooling device that it can take extreme cold. The air conditioning unit, however, also has a limit of 32 degrees Fahrenheit. Anything lower than this and the moisture inside the ac unit will ice up the evaporator coils. 

Ironically, frozen cold coils would fail to perform and struggle to meet the thermostat setting, let alone chill the air. Leaving you sweaty, muggy, and hot-headed.