It seems like a paradox: It’s getting hotter outside in the Atlanta-area, but your central air conditioner is covered in a thick sheet of ice. However, this is a common problem homeowners have with their air conditioner during the cooling season. So, it’s not out of the ordinary. There are 2 common reasons why this happens:
1) Restricted airflow
By “airflow” we mean the amount of air flowing over the air conditioner evaporator coil (the A-shaped part of the inside unit). When airflow is restricted or reduced, there’s less heat for the evaporator coil to absorb, causing the temperature to drop to freezing levels. Then, when humid air comes into contact with the coil, moisture condenses on the coils (like how water beads up on a cold glass of water in summer) and then freezes. Several things can cause restricted airflow:
a) Dirty air filter (change your filter once a month)
b) Dirty evaporator coil (a professional needs to remove and clean the coil)
c) Blocked return grills (move any curtain or furniture blocking return vents)
d) Closed vents (don’t close vents in unused rooms, your A/C is sized to work with a certain amount of airflow)
e) Blower motor is weak/not working (have a professional fix the motor)
There are a few other causes, but these are the usual suspects.
2) Low on refrigerant
Your air conditioner uses refrigerant to move heat from inside your home to the outside. But when it’s low on refrigerant, there’s a pressure drop in the evaporator coil. As the pressure drops, so does the temperature, causing the coil to get to below freezing temperatures. So, the same thing happens like when there’s restricted airflow.
a) Humid air hits the freezing coil
b) Water beads up
c) Water freezes
WARNING: If you’re low on refrigerant, that means there’s a refrigerant leak. So, a technician should first locate and repair the leak. THEN they can evacuate and recharge the system with refrigerant. Anyone who tries to top you off with more refrigerant without looking for a leak isn’t doing their due diligence.
Here’s general troubleshooting you should try to resolve this icy issue before calling a professional:
1) Turn off your air conditioner.
2) Let your air conditioner defrost.
3) Change your air filter.
4) Open up all the air registers in your home.
5) Make sure none of your furniture or drapes are blocking return vents.
If your air conditioner still freezes up when you turn it back on, call an air conditioner contractor for help.