As a heating and cooling company, we often hear about a customer's system being frozen, and thus not working properly to keep their space comfortable. You may be asking, why does the A/C unit freeze up in the first place?
There are two reasons why this may be. First of all, insufficient airflow could be a culprit. When there is no air traveleing through the system, there is nothing keeping any condensation from building up in the evaporator coil. With no air flowing consistently over the coil, it freezes. Second of all, there could be issues with the refrigerant. Refrigerant regulates the temperature in your system. If there are any problems, this could lead to the unit freezing.
We reccomend a homeowner try one trick before calling a qualified technician. Take a look at the filter, if it needs to be changed, replace it with a new filter and then cut the system off for a couple of hours to ensure all the ice has melted. If the freezing reoccurs, cut the system off to prevent any damage. Don't be afraid to call a qualified service company to investigate the matter further!