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Why Should the Refrigerant Line on my AC be Insulated?

Most HVAC specialists recommend that the refrigerant line on your AC be insulated. But what does that mean?

First, let’s talk about what the refrigerant lines do.

A typical residential AC unit has two copper lines that exit the building and run into the condenser unit. One is called the “warm” line or “liquid” line. This line is typically smaller, and it carries the refrigerant in a liquid form and sheds heat as it moves. This line is not typically insulated because it must get rid of heat.

The other line is called the “cold” line or “suction” line. This is the larger line, carries a cooled vapor and should be insulated.

Suction line with damaged insulation
Suction line with new insulation

What happens if the line is not insulated?

When the insulation begins to fail, more and more energy is lost and usually it makes your equipment work harder to maintain temperature. Insulation protects against condensation and helps maintain moisture control. If moisture penetrates the insulation, surrounding the cold pipe, energy is lost and can even lead to freezing. This in turn can lead to bigger problems down the road.

Frozen line

Typically, the insulation used in this application is a rubberized or foam material and is low cost. An HVAC professional can install it quickly and easily.

Don’t get caught with AC problems that can escalate. Make sure to check your suction line at least once a year, especially in Florida where the UV index can get pretty high. Insulation can become damaged quickly by high UV. In all my years doing home inspections, I have never seen this insulation last for extended times. Just add this to your home maintenance list!