Why is My A/C Freezing UP? | R. A. Styron | Chesapeake VA

It’s happened to most homeowners, you come home or wake up to no A/C and your air conditioning system has ice on it. Sometimes the frost can build up so badly that the whole system is a full-on block of ice. Why would a machine meant to put out cold air start to build up ice, you might ask? Well, sometimes it a fairly simple issue that can be fixed by you, while other times you may need to call in a professional.

Without fail, your first step to remedying the problem is to turn the A/C system off. The longer the A/C continues trying to cool, the ice will just continue to build doing more harm to your system. If your system is completely iced over, it may even be beneficial to turn your thermostat to heat and allow it to run speeding up the thawing process. Just be sure to watch the water levels at the indoor unit. If the drain pan under the system becomes full it may spill over leading to water damage.

Now that the system has thawed, lets get down to the problem at hand.

Low Refrigerant:

Often times, systems that are low on refrigerant will freeze up. If your system over 8 years old, it is likely using a refrigerant called R-22. If your system is a bit newer, it should be using the updated refrigerant called 410-A.

No matter which of the two refrigerants your system uses, if it is low the system will fail to function properly. If something happens and the refrigerant pressures are too low, the pressures change will lead to the refrigerant to act differently leading to the icing of the system. The change may be minimal and not too noticeable at first, but too much ice will start to affect the airflow until you are left with no a/c at all.

Once the A/C is thawed out trying turning it back on. If you are now getting air flow through the vents but it’s not cooling, you probably have a refrigerant issue. Because refrigerant is potential harmful to the environment it is EPA regulated and you must carry the proper handling licensing to purchase it. The only way to properly repair the system is to call in a professional to weigh in and adjust the refrigerant levels to exact specifications. Depending on how low the levels are, the technician should offer to perform a leak search to find and repair the leak before adjusting the system back to appropriate levels.

Proper Air Flow:

Dirty Vs. Clean Filter

A/C units that are not getting enough air flow will not have enough heat from the warm air in your home to prevent the condensation on the coil from turning to ice. Many times this is caused by a dirty and/or clogged filter. We cannot stress enough, the importance of a clean filter. Replacing dirty filters is the most inexpensive month maintenance you can do to prevent extremely costly repairs to your system. If you find a dirt filter you should change it out immediately while the system is thawing out.

Rather you find a dirty filter or not, it would be beneficial for you to check all your vents, ductwork, and dampers if you have them. Be sure that the vents are free and clear of furniture or any other obstructions. People will often close off rooms and vents to save from cooling an unused space but in reality they are only making the A/C work overtime. Damaged ductwork can also lead to the system icing up. Be sure to check your ductwork for collapsed areas or ductwork that may have developed holes or come unattached.

If you find any areas of concern with filters, ductwork, or closed off vents make the corrections before turning the system back on. Once this is done and your system is blowing cool air again you should be in the clear. We have a blog (here) dedicated to filter replacement if you need help deciding on the best replacement filter.

Dirty Coils:

Dirty coils are in the top three most common problems our technicians find in the summer months. When the coils become caked with a layer of dirt or dust air flow will again be a problem leading the freezing of the coils themselves. While coils are easily cleaned they can become damaged, rather easily. If you are planning on cleaning the coils yourself, be sure not to damage or misshape the coils during the cleaning process. They are easily bent out of shape leading to even greater air flow concerns and possibly even a complete replacement of the coil.

Bi-annual check ups are a sure way to prevent buildup on the coils. Maintenance technicians will properly clean the coils with a specialized solution and brushes to achieve complete cleanliness without damaging the fins.

If you currently have no annual or bi-annual maintenance plan we strongly encourage you to start one. Maintenance will drastically increase the life expectancy of your system while decreasing both your monthly energy costs and unexpected breakdowns. There are plenty of important reasons to start maintenance no matter the age of your system, which you can read about on our maintenance blog, here.

Damaged Blower Fan:

The system’s blower fan allows the cold air to get where it needs to go for the system to operate properly. It helps move the cold air by sucking hot air from your home, replacing it with the cooler air. The effectiveness of your A/C system creating cool air to blow through your vents is 100% dependent on properly balanced airflow and air pressure.

A broken or damaged blower fan will significantly change the airflow inside your system. The changed airflow will allow the condensation to build up on the coils or the refrigerant line to freeze up. Both symptoms that will eventually cause the system to freeze up and not function properly.

Only a qualified service technician will be able to properly diagnosis and replace a blower motor.


While there is always a possibility of other problems occurring, these are the top four reasons system may be iced over. As we said in the beginning, the first thing you should do is shut the system down. There is no way for anyone to diagnosis or repair a system that is iced up.

If you know that you are in need of a professional hand for routine maintenance or repair, R. A. Styron is your Hampton Roads leading Air Conditioning contractor. You can schedule your consultation online through our website or over the phone at 757-420-5488. You will always get someone from our company on the other line no matter the day or time.



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