For residential gas equipment, what does the term "listed equipment" refer to?

The term "listed equipment" refers specifically to equipment that has been tested and certified by a recognized testing laboratory to meet specific safety standards. This ensures that the equipment is safe for use in residential settings and complies with local, state, and national codes. When equipment is listed, it signifies that it has undergone rigorous testing for performance, safety, and reliability.

The safety certification process invigorates consumer confidence and encourages proper installation and maintenance practices. It is essential for compliance with regulatory requirements, and using listed equipment is often a prerequisite for obtaining necessary permits during installation. The other choices, while they may have merit in other contexts, do not accurately reflect the significance of the term "listed" in relation to safety and compliance standards.