Pipe insulation

A/C Pipe Insulation

Identify the correct AC line to insulate. A typical residential AC unit has two copper lines that both exit the building exterior and run to the outside condenser unit. Only one of these copper pipes, the cold line, should be insulated. This is called the “suction” pipe and is typically the larger of the two pipes.

Refrigerant lines are two copper lines that connect the outdoor air conditioner or heat pump to the indoor evaporator coil. The larger line typically carries a cool gas and is insulated. This is commonly referred to as the suction line, but it is also called the return line or vapor line.