True or False: It is common to use two layers of insulation material to meet minimum duct liner thickness.

The statement regarding the use of two layers of insulation material to meet minimum duct liner thickness being false is accurate because the minimum thicknesses specified in standards and codes can typically be achieved with a single layer of properly selected insulation material. Most building codes and energy efficiency guidelines set forth minimum requirements that specify a single layer of insulation that meets the necessary thermal resistance (R-value).

Using two layers of insulation is generally not a standard practice for residential or commercial duct insulation unless there are specific performance needs or unique circumstances that necessitate additional thickness. This approach can also increase installation costs and may not provide additional benefits in terms of energy efficiency beyond what a single layer can achieve, provided it meets the standards.

While insulation practices can vary based on specific project requirements or building codes in different regions, the default assumption in many standards is that a single adequately thick layer is sufficient for meeting insulation requirements. This perspective makes the assertion that “it is common to use two layers of insulation material to meet minimum duct liner thickness” inaccurate.