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Serving West Austin & Surrounding Areas

Outdoor AC Unit Freezing In Summer - Causes & Solutions

frozen system

It’s another hot summer day in Austin, but your outside unit is white and glistening. It’s a layer of ice, but how? And is it normal?
Whether you’re seeing ice for the first time or your outside AC unit freezing up in summer seems to be a pretty regular occurrence, the first thing you’ll want to do is shut your unit off and call a professional.

When your AC freezes up, something’s wrong – not only does ice dramatically reduce efficiency, but when left unattended, it can lead to a complete breakdown of the unit.

In order to properly diagnose and correct your icy AC unit, a professional will need to assess the system in person. Here’s what you can potentially expect, and what you can do at home to correct and prevent the issue.


A lack of airflow caused by an obstruction somewhere is a very common cause of a frozen outdoor unit in the summer. Airflow can be obstructed in a couple of ways: a clogged air filter, yard debris, closed vents, leaks in the ductwork, and blower fan failure.

Airflow Solutions
Turn your AC off and let the unit thaw out. In the meantime, check your air filters, the area around your unit, and your AC vents.

Filters: Your AC filters should be clean enough for air to pass through; change 1-inch filters every 1-2 months in the summer.
Debris: Clear away debris and obstructions from the outside unit, to ensure air can flow freely. Your AC unit needs quite a bit of breathing room, so it’s important to keep it free of leaves and grass, and to avoid stacking wood or planting shrubbery within 3-5 feet.
Vents: Your HVAC unit was designed to cool your home efficiently, according to layout and square footage. When you close vents to redistribute air flow, there are unintended consequences. Closing some of your vents can disrupt your system’s equilibrium in subtle ways, impeding air flow rate and increasing the demand on your system.

If you’ve checked your filters, the outside unit and your vents, and ice returns to your unit when you turn it back on, it’s time to contact us for a professional assessment.

Prevention for Issues with Airflow
To prevent potential issues with airflow, change your filters often, keep the outside unit free from obstructions, keep all the vents in your home open, and schedule regular HVAC maintenance.
During regular maintenance, we will remove all debris and conduct a thorough inspection of your system.


Imperceptible pinhole leaks or improper coolant charging (not having enough coolant) can lower your refrigerant’s pressure and temperature. When this happens, the moisture passing over your coils turns to ice.
Improper charging doesn’t happen very often unless you had a unit installed that wasn’t pre-charged by the manufacturer. If you recently had a new installation, it’s possible that the installation technician did not add enough coolant to your system.
A leak is a much more likely cause for an AC coolant issue, and it’s unfortunately one of the more serious AC problems a homeowner can run into because continuing to run an AC low on coolant can result in severe damage to your system.

Refrigerant Solutions
You may be wondering if you can simply top off your home’s AC coolant, and the answer is no. Air conditioning coolants aren’t liquids you can simply pour into an opening with a plastic funnel. And while there are no regulations dictating that your AC coolant needs to be refilled by a professional, these products can be deadly when handled improperly.

Most refrigerant leaks are so small that they can only be detected by a refrigerant sniffer, and fixing a leak isn’t as easy as wrapping duct tape around the affected part. If there are issues with your coolant, a qualified HVAC tech will need to repair any leaks and recharge your coolant.

Refrigerant Leak Prevention
By far the easiest way to prevent refrigerant leaks from occurring is to get regular maintenance for your AC. During regular maintenance, we check the indoor coil, refrigerant lines, and outside unit for possible leaks.


Your AC unit works best when it receives plenty of airflow. When your unit’s coils are dirty airflow is restricted, which can lead to various problems including ice formation and damage to the compressor. In addition to seeing ice on the unit, you may see water puddles and notice that your AC isn’t cooling as effectively when your coils are dirty.

Solutions for Dirty AC Coils
To prevent your cooling system from breaking down, shut the unit off until a professional can come clean or replace your coil.
Your AC system has two coils: the evaporator coil and the condenser coil. Your evaporator coils are located inside your air handling unit, while the condenser coils are located on the outside of your outdoor unit. While you can clean your AC’s coils yourself, the training and specialized equipment, including a variety of protective wear, an HVAC professional can utilize will make this process much faster and more effective.

Dirty AC Coil Prevention
You can prevent dirt buildup on the evaporator coil by changing your air filters regularly. You can prevent additional dirt buildup outside on the condenser coil by hosing your unit off regularly.
Setting up regular AC maintenance is the best way to prevent dirt buildup on your AC’s coils. A skilled technician will clean the coils and ensure the rest of your system is working properly.


Ice can form on your AC when the air conditioner keeps working even after you’ve reached the set temperature in your home. This issue can be caused by a broken thermostat, faulty wiring, a damaged fan, clogged drains, and more.

Solution for Faulty Parts or Wiring
To properly diagnose the root of your issue, call a licensed HVAC professional to inspect and repair the unit.

Fault Prevention
Our seasonal maintenance plans are designed to catch potential issues with your AC early, so that you can stay ahead of costly repairs or replacements. During maintenance, we check the indoor and outdoor components of your HVAC system thoroughly to ensure optimal performance and function.