ESCO Air Conditioning Practice Exam 2025 - Free AC Certification Practice Questions and Study Guide

Closed-cell foam insulation is commonly used for refrigerant lines due to its excellent thermal resistance and moisture barrier properties. This type of insulation effectively minimizes heat transfer, which is crucial for maintaining the efficiency of the refrigerant in the lines. The closed-cell structure of this insulation prevents moisture accumulation, which can lead to corrosion of the refrigerant lines and reduce the overall efficiency of the air conditioning system.

In addition to its thermal properties, closed-cell foam insulation is also durable and resistant to water vapor, ensuring the integrity of the refrigerant lines over time. This is particularly important in HVAC applications where consistent performance is essential for energy efficiency and system reliability.

The other types of insulation, while useful in different applications, do not offer the same combination of moisture resistance and thermal performance required specifically for refrigerant lines, making closed-cell foam the preferred choice for this purpose.