You've probably seen advertisements for used cars advertising "ice cold" air conditioning. Your air conditioner is supposed to keep you cool, so having one that can produce frigid temperatures sounds good, at least at first. However, your home's air conditioning system shouldn't produce temperatures that leave you reaching for the nearest sweater.

In fact, air conditioning manufacturers design their systems to provide a consistent temperature drop between the return and supply vents. If your air conditioning system is suddenly producing much colder air, that's often an indication of one of these three underlying problems with your home's AC system.

1. Refrigerant Leaks

The relationship between refrigerant pressure and temperature is often one of the hardest things for homeowners to understand. It's logical to think that losing refrigerant will reduce your system's cooling ability, but the situation isn't quite so simple. Generally speaking, lower refrigerant pressure at the evaporator will result in lower temperatures.

This relationship means that a refrigerant leak will often produce icy cold air at your vents, at least at first. Unfortunately, colder temperatures will also lead to ice forming on the evaporator coil. Given enough time, this ice will stop the refrigerant from absorbing heat altogether, causing your system to shut down until the ice thaws and the cycle repeats.

2. Metering Device Restrictions

Most modern central air conditioning systems contain a metering device known as a thermostatic expansion valve or TXV. Since your evaporator coil needs a precise amount of refrigerant pressure to create the correct temperature drop, the role of the TXV is to meter refrigerant so that it always receives this amount.

However, contaminants in the system can cause the TXV to become clogged. These devices can also fail due to age, sticking in a partially closed position and creating a restriction. Either way, insufficient refrigerant will reach the evaporator coil, resulting in the same ice-cold symptoms you'd normally experience with a refrigerant leak.

3. Thermostat Problems

A faulty thermostat can also cause a chilly home, but usually with drastically different symptoms from a refrigerant issue. With a leak or restriction, you will notice icy cold air from your vents, but your home may not fully cool. On the other hand, a faulty thermostat will produce relatively normal cool air from your vents, but the overall temperature in your home will continue to drop.

If you think your thermostat may be faulty, try raising the setpoint several degrees above the current temperature in your home. Your AC may need to continue running for a few minutes, but it should shut off relatively quickly. If the system keeps running after a few minutes go by, that strongly points towards an issue with your thermostat. 

Speak to an AC repair service to learn more.