An AC unit uses a set of evaporator coils to cool the air in your house. As a fan pushes, the hot air from inside your house over the coils, the refrigerant inside the coils vaporizes. During the refrigerant's phase change from a liquid to a gas, it absorbs heat from its surroundings. However, if there is not enough air flowing over the coils, they can absorbs so much heat, that the water vapor in the air flowing over the coils freezes. When this happens, you need to deal with the ice before it causes serious problems for your AC unit. 

Effects of Frozen Coils

Air must be able to flow through your AC coils to get to your house. If your AC coils freeze over, they can completely block airflow. Without enough cool air reaching your house, your AC unit can run for hours on end without affecting the temperature in your home in any way. Thus, you waste a lot of energy and money. 

Causes of Frozen Coils

There are a few different causes of frozen coils. For example, if you have a severely dirty air filter, it can restrict airflow to the point that water vapor begins to freeze. A second problem is that your evaporator fan might be broken or the the fan motor might have a blown capacitor. In the case of a dirty filter, you should be able to swap out the bad filter for a new one on your own, but in the case of a malfunctioning fan, you will need to call in a professional to make repairs. 

Getting Rid of the Ice

Once your evaporator coils have iced over, you will need to deal with the ice before your coils will begin working properly. Use these steps:

1. Turn your thermostat to the off position. As long as your system is running, the ice will stay intact. 

2. Place buckets and/or towels under your evaporator to catch water as it melts off the coils. 

3. Do not chip at the ice. If you feel like you need to speed up the melting process, use a hairdryer to melt the ice. Chipping can damage the coils and create a refrigerant leak. If you have a leak, federal law requires that you call in a professional to make repairs. 

4. Deal with the cause of the problem. Start by changing the filter ( if needed), and if you still have a problem, call in a professional HVAC technician to make repairs. 

De-icing your coils is not complicated, so even if you don't haven't been to school to learn how to work on HVAC equipment, you should be able to get ice off of your evaporator coils. However, you may not have the skills to make repairs. At least you can call in an HVAC company like Sunbelt Service Pros and begin the de-icing process while you wait for the technician to show up.