What Is a Filter Drier and Why Do AC Systems Need Them?

When most homeowners think of filters in AC systems, they envision air filters. All central AC systems have an air filter. Typically constructed of pleated paper, it’s designed to remove contaminants from the air. Your AC system, however, probably has another type of filter: a filter drier.

What Is a Filter Drier?

A filter drier is an AC system component that’s designed to remove contaminants from the refrigerant. It’s typically found in the liquid line. The liquid line is an uninsulated copper pope that carries refrigerant in the form of a warm liquid. As the warm refrigerant travels through the liquid line, it will pass through the filter drier.

How Filter Driers Work

Filter driers work by cleaning the refrigerant in AC systems. They are known as “filter driers” because they dry the refrigerant by removing moisture.

Only refrigerant should flow through your AC system. If moisture enters your AC system, it will introduce contaminants. Moisture can even have a chemical reaction with refrigerant that results in the creation of hydrofluoric acid. Over time, hydrofluoric acid can eat away at your AC system from the inside out.

A filter drier will keep your AC system dry by removing moisture from it. Refrigerant must travel through the filter drier. If there’s any moisture in the refrigerant, the filter drier will remove it. Most filter driers feature granules that will absorb moisture and trap debris – all while allowing refrigerant to pass through them.

The Your AC System Needs a Filter Drier

Your AC system needs a filter drier to protect against refrigerant leaks. Under normal circumstances, refrigerant shouldn’t leak out of your AC system. But corrosion can eat through pipes and other parts while subsequently allowing refrigerant to escape. A filter drier will protect your AC system from leaks such as this by removing moisture.

A filter drier will improve the performance of your AC system. Your AC system may struggle to cool your home if there’s an excessive amount of moisture in it. Moisture will inhibit the refrigerant from absorbing heat. The moist refrigerant may still absorb some heat from your home’s interior, but it may fail to absorb a sufficient amount of heat. The end result is less cooling power.

With a filter drier, the refrigerant will absorb more heat. It will pull more heat out of your home, resulting in cooler air.