For an air conditioning system to freeze does not mean that we have ‘a champion of a machine’.  On the contrary, if the air conditioner freezes or frosts, it is indicative of a malfunction or issue of the A/C system.  This is where we say “Houston, we have a problem!”

A common problem is when an air conditioner freezes up.  You will know your A/C is freezing up when you notice ice or even see the outdoor unit freeze completely.  Although, this can happen on both an indoor and outdoor unit, most people call for A/C and heating services when the issue has worsen on their HVAC unit and when it's more visible to them. 

Signs A/C Is Freezing Up

Before we realize that there is an issue with our air conditioner, our cooling system has been presenting hints that there is a problem with it.  It’s not until it stops working that we decide to put the pieces of the puzzle together.  Let’s go over some of those ‘signs’ our air conditioning system was sending down the pipeline:

• My air conditioning does not pull enough air.  A drop in the flow of air that propels our air conditioning is indicative of something very clear—something is very wrong.  Not enough air through the indoor exchanger (internal radiator). The air conditioners drive (pull) the same amount of air that it collects. If this heat exchanger freezes, the air conditioning unit becomes clogged and begins forming a layer of ice over its entire surface, preventing the air to be expelled in the same way—in other words, ‘Air conditioning will not pull enough air indoors.’
• My air conditioning is dripping water or ice.  Generally, when the air conditioner is frozen usually it creates pieces of ice and on many occasions, that ends up entering the indoor fan (blades) which pulls ice and the drops of water is the ice thawing.
• Noise in the A/C unit.  There may be instances where you can hear a "crunching" sound in the A/C unit as the system is defrosting from the ice that it has accumulated.  This does not always occur, but it is a sign that something is very wrong with A/C.

Possible Reasons Why A/C Is Freezing Up

There are several factors that may be causing A/C freezing up.  Some reasons are caused by the lack of maintenance and other reasons may be more serious.

• Dirty Filters:  The most common cause for A/C freezing up is having extremely dirty A/C filters.  It is also the easiest preventative step an owner can take.  The freezing up of the air conditioning unit can be avoided if we take a proper maintenance.  Periodic filter cleaning is one basic but important step.  Dirty filters prevent the A/C from being able to expel the cold air.  Clean filters may be a simple solution to the problem.
• Restrictions in the Metering Device:  As in the case of filters, a dirt metering device, produces the same effect.  There will not be enough air flow in the A/C unit.  This gradually freezes the air conditioning unit.  This problem tends to also be due to poor maintenance, since keeping air conditioner filters will prevent dirt to pass to the metering device.
• Not Enough Freon:  This is the most common cause for A/C unit not working.  Air conditioner freezes as if out a freezer, since a lowered gas pressure directly impacts an evaporating temperature (temperature which reached the refrigerant to the indoor unit).  The solution in these cases will be to find the leak, repair it and finally recharge freon.

Before these potential problems occur, we should act swiftly and prudent when it comes to regular maintenance of A/C unit.  If you run into serious A/C problems, you should call for the services of HVAC System Repairs specialists.