What measurement is used to indicate the effectiveness of insulation in ducts?

• A. R-value
• B. BTU
• C. CFM
• D. FPM

Answer: (A)

The R-value is the standard measurement used to indicate the effectiveness of insulation in ducts. It represents the material's resistance to heat flow; a higher R-value indicates better insulating properties. In the context of ductwork, insulation with a high R-value helps to reduce energy loss, improve system efficiency, and maintain climate control within a building.

The other measurements listed do not indicate insulation effectiveness. BTU (British Thermal Unit) measures heat energy, CFM (Cubic Feet per Minute) refers to airflow volume, and FPM (Feet per Minute) measures air velocity. While these factors are important for overall HVAC performance, they do not specifically relate to the insulating properties of duct materials like the R-value does.