Air conditioners always seem to freeze when temperatures are the hottest. Worse still, there’s nothing you can do to make it thaw faster. While an AC typically thaws in just one to three hours, it can sometimes take up to a day.
While you wait for it to thaw, take time to learn about why ACs normally freeze up and how to prevent them from freezing in the future.
Understanding AC Freezing Issues
What causes an air conditioner to freeze up? At its heart, this problem relates to the Joule-Thomson effect and the role of your evaporator coil. This effect is the idea that changes in pressure cause changes in temperature.
The Joule-Thomson effect is one mechanism behind how an AC works. Before the AC sends refrigerant into the house, it compresses it. Then, the refrigerant absorbs heat in your home to take the heat outside. The refrigerant passes through the condenser coils and eventually expands again when it passes through the evaporator coils.
So, what causes an AC unit to freeze up? Ultimately, this happens when the evaporator coil freezes. This can happen because of reduced airflow, low refrigerant levels, or thermostat issues.
Reason 1: Restricted Airflow
If you keep asking yourself, “Why does my AC keep freezing?”, your filters or vents could be to blame. Blocked airflow prevents warm air from flowing over the evaporator coils.
What causes air conditioner to freeze up? Normally, warm air flows over the evaporator coils, keeping them from getting so cold that they freeze. Eventually, ice forms on your AC unit.
This problem typically occurs if you have dirty filters or blocked vents. It can also happen because of faulty fans.
Reason 2: Low Refrigerant Levels
Why does my air conditioner freeze up when the refrigerant is low?
When your AC works properly, the refrigerant transfers heat from inside your home to outside. A lack of refrigerant causes your coils to get too cold, eventually freezing up.
So, why is my air conditioner freezing up? Technically, the evaporator coil is the primary component that is freezing up. If the refrigerant levels are low, the evaporator coil can freeze. Unfortunately, the same problem will happen again unless you call a professional HVAC technician.
Once an HVAC technician fixes your AC, be sure to schedule annual maintenance checks. During these visits, the HVAC technician will check the refrigerant levels. Refrigerants can be hazardous to handle, so never try checking these levels yourself.
Reason 3: Thermostat and Temperature Issues
Why does my air conditioner freeze up when nothing seems wrong with it? What causes the air conditioner to freeze up?
When your thermostat is set too low, your air conditioner will keep running instead of switching off. This problem becomes even worse if it is very hot outside. If the AC keeps running, it will eventually freeze.
The easiest way to fix this problem is by setting your thermostat to a higher temperature. During the day, experts usually recommend setting the temperature to 78 F, although this can vary based on your comfort level, the temperature outside, and other factors. You can realistically lower your interior temperature to about 10 to 15 degrees below the outside air, so consider increasing your thermostat’s setting on scorching days.
Immediate Steps to Take When Your AC Freezes
When your AC freezes, act quickly to prevent further damage to your family’s air conditioning system. Turn off and unplug your unit immediately as expensive components can get damaged if the power stays on.
1. Wait for It to Thaw
Next, you’ll need to wait for the AC to thaw. If it is covered in ice, don’t try to chip it off yourself. Other than potentially hurting yourself, you could accidentally damage one of the AC’s important components.
2. Look for Dirty Filters
It can take up to 24 hours for the AC to thaw fully. Once it thaws out, check the filters to see if they’re dirty.
If you’re mechanically minded, clean them according to the manufacturer’s specifications. As some filters must be changed instead of cleaned, check your owner’s manual. If you’re uncomfortable doing the cleaning or changing of the filters and have no experience in this area, it’s best to leave it to the professionals.
3. Check for Water in the Drain Pans
Inspect the drain pan and the unit inside for water. Often, a frozen AC leads to extra water in the drain pan, which can damage the components. This problem needs fixing right away.
4. Get Help From an HVAC Professional
The most important thing is turning off the unit and calling an HVAC professional for help. Although you might be tempted to pull your hair back in a ponytail, throw on a pair of old jeans, and get dirty, this isn’t a DIY project like keeping your grass green in the heat. Many issues, like recharging refrigerants, require special training.
An HVAC technician is certified in handling refrigerants and knows how to fix a frozen AC. More importantly, they can figure out the underlying cause that makes your air conditioning unit freeze up.
Preventing Future AC Freezing Issues
If you often experience AC freezing issues, it’s important to call an HVAC technician for help. These simple steps can prevent future problems:
- Get routine maintenance and timely repairs
- Set your thermostat higher on hot days
- Ask a professional home ac repair service to inspect your unit
- Clean your air filter
Get Your AC Ready for the Heat
What causes AC to freeze up? Typically, an AC unit freezes because something is stopping the refrigerant from transferring heat properly. That may happen because of a high thermostat setting, restricted airflow, or low refrigerant level.
No matter the cause, a home ac repair service can help you find a solution. If you keep running the AC, it can damage the components. With the proper maintenance and repairs, your AC unit can run at its best.
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