Air Conditioner Freezing Up? Here’s the What, Why, and How for AC Freezing Issues
During a hot and humid summer evening, you are relaxing on your couch, watching a nice movie in the comfort of your chilled room, and suddenly the air conditioning stops working. There is no cold air coming out of the appliance, and you are forced to investigate your air conditioning unit with great stress. In the midst of summer, to your surprise, you find the air conditioner freezing up!
Although it is a rare event of misfortune, air conditioners do occasionally freeze up. You may start to wonder how ice got into your air conditioner and why it made your air conditioner stop working. Let us see how this happens and how we can prevent such an instance from happening again.
What Causes an Air Conditioner to Freeze Up?
Wondering what causes an air conditioner to freeze up? How is this even possible during the summer heat? Even though the exact cause of the air conditioner freezing up may vary, the underlying principle is the same. Moisture condenses on the air conditioner coils, which then freezes at a sufficiently low temperature.
The route through which air conditioner freezing occurs can be different. Let’s see some of them along with their solution:
Dirty Filters Causing a Blockage
Perhaps the primary cause of an air conditioner freezing up is a clogged AC filter, which reduces the airflow over the air conditioner coils.
Before reading further, go ahead and get a quick overview of how an air conditioner works.
Now that you know the workings of an air conditioner, you know that the refrigerant absorbs heat from the indoor air and transfers it outside. This makes the air around the evaporator coil cold.
In perfect conditions, the warmer air passing through the filter keeps the evaporator coil from freezing up. But when it is clogged, there is a lack of airflow, which allows the ice to accumulate over the coils once the moisture in the air condenses.
The obvious solution to this problem is to check your AC filter, and if it is dirty or clogged up, give it a thorough clean up. You can wash the filter as well. But be sure to completely dry it off before putting it back in for use.
If the filter has too much dirt or debris on it, it might be a good idea to get a new filter altogether, rather than cleaning up the old one.
Tune up your air conditioner especially at the start of the season and every few months or so depending on your usage. You can use a smart AC controller to be notified when your filter likely requires cleaning. This will help keep your air conditioner in great condition and help avoid any freezing up or other problems!
Low Thermostat Setting Increasing Condensation
Some people keep the temperature downright low while sleeping at night and pile up on the blankets.
In such an instance, in particular with old air conditioners, the condenser coils can accumulate ice over them. This is because the moisture in the air condenses over those coils. If you leave the air conditioner running all through the night, the ice can grow to a thick layer.
The remedy to this problem is to turn off your AC as soon as you identify there is ice. Running the air conditioner in fan mode will increase the rate at which the ice melts. For a permanent solution, give your air conditioner a thorough clean over and keep the temperature a few degrees above the minimum for prolonged usage.
It’s best to avoid running your AC for extended periods at extremely low temperatures. This also greatly depends on the outside temperature but more on that in the next section!
Running AC on Cold Nights or Winters
A great advantage of air conditioning is that it dehumidifies the air. This is why it is often used in the winter months as well if the humidity gets too high for your comfort.
During the winter months, when you turn on your air conditioner, even for dehumidification, air conditioner coils can get frozen. This happens because of the lack of warm air passing over those coils.
As explained before, the air around the evaporator coils can get cold during operation, and a constant supply of warm air is needed so that they do not freeze over. When the temperatures drop to the low 60s, there is not enough warm air to prevent the coils from freezing, and you get a buildup of ice on the coils.
This severely hampers the ability of the air conditioner to dehumidify the air and also its efficiency.
To avoid this problem, turn your air conditioner to fan mode and keep it running for a while until the ice thaws.
Avoid using your air conditioner on very cold days – here’s more on maintaining the best humidity levels for your home. When the nights turn super cold you can use a smart thermostat for ducted ACs or mini-split thermostats. You can program these devices to shut your unit off as the temperature drops.
Dirt and Dust Clogging up the Evaporator Coil
If you have an old air conditioner, which has not been serviced in a while and is covered in dust and gunk, then there’s a high chance it would freeze up after prolonged use.
The buildup of dirt on the coil hinders the heat transfer between the coil and refrigerant. With the refrigerant making the coil extremely cold, and without enough heat transfer taking place, the temperature eventually falls below 32 degrees, forming ice on the coils.
The immediate solution is to run the air conditioner in fan mode for a while and let the ice thaw. For a more prolonged remedy, take out the front cover of your evaporator coil, and clean them with a soft brush or cloth. You will have to do this after the ice thaws, though. Be careful not to use a sharp object, as it could damage the coils.
Regularly service your unit and keep it in top shape! The better you take care of your appliance, the longer it will run.
Low Refrigerant Levels
Low refrigerant is a big problem in itself for air conditioners, but it can cause air conditioner freezing as well. Due to low refrigerant, the pressure in the coils is very low, causing the coils to get cold. Combining this with cold outdoor temperatures as well, condensate can start to freeze on those coils.
In this scenario, there is most probably a leak somewhere in the system, or your refrigerant lines can be damaged.
In the case of a leak or a mechanical problem, it is better to call over an HVAC professional who will go over your air conditioner thoroughly and identify the leak.
The technician will also top up the refrigerant to the recommended levels, ensuring your air conditioner is working in perfect condition.
Again, the best way to keep your air conditioner in great shape is to focus on its maintenance. Regular upkeep will help prevent any clogs or leaks & identify early warning signs. However, with the passage of time, this can get harder to avoid!
By now, you should have all your answers to your air conditioner freezing up problems. Give your air conditioner a good clean-up, take care of your AC filters, and enjoy your air conditioning!