2 Possible Reasons Why Your Central AC Unit Keeps Freezing Up


After discovering that your home is not as cool as it should be with the air conditioner running, you may have looked outside and noticed a sheet of ice blocking the air vents. If so, there are a couple of possible reasons why your central AC unit is freezing up, especially if it keeps happening on a regular basis.

1.  Thermostat Is Turned Down Too Low at Night

One possible reason why your AC unit keeps freezing up is that you are turning the thermostat down too low at night. Since the air conditioner turns on in response to the thermostat's signals, it does not stop running because the air physically around it is too cold.

If you turn the setting down below the outdoor temperature, the unit will continue to run. Along with the cold air produced by the condenser, the external air freezes any moisture inside and outside of the unit. This then causes the condenser to freeze up, removing its ability to produce cold air and circulate it through your home.

To see if this is the case, try making sure the thermostat's temperature is set above that of the outdoors. If your unit keeps freezing up, you may have another issue to contend with.

2.  Coolant Levels Are Low Because of a Leak

If you do not believe that the AC unit is freezing up from the thermostat's setting, the issue could lie with a coolant leak within the system. When this happens, not enough coolant is circulated evenly throughout the condenser. 

If a large amount of coolant is inside the coolant at one time after a brief period of having no coolant, ice will start to form within the unit because it reaches subzero temperatures. And, since the main reason why coolant levels go low in the closed system is a leak, the problem will only get worse as the coolant continues to escape.

Along with the unit freezing up, you may also hear a hissing noise coming from it while the AC is running. This noise is the sound created by the coolant escaping through a hole in the line.

If you have ruled out that the problem is caused by a low setting on your thermostat overnight and feel that you have a coolant leak, you need to have it repaired as soon as possible to keep your AC unit running and prevent contamination of the surrounding area by the coolant. Contact an HVAC services company to schedule a time for them to inspect your unit and fix any damage they may find. 


24 February 2019

Cool off Your AC Bill

Every summer, I agonized over energy bills that would shoot into the stratosphere as a result of my efforts to keep cool in the heat. Every time I turned the temperature down, my bills increased. This summer, I decided to take some of the control over my energy bill back. I installed reflective film on my windows that reduced the amount of light and heat coming into the house. I started serving more cold meals or asking my husband to barbecue outside, so that my air conditioner didn't have to compete with the hot stove, and I started doing laundry at night to reduce appliance heat in the house at peak times. I also had ceiling fans installed. So far, the difference in my bill has been tremendous. This blog is a way for me to explore other ways to reduce energy drain during the summer months.