What does R-value represent in insulation performance?

• A. R-value measures the color of insulation.
• B. R-value measures resistance to heat flow; higher R-value means better insulation.
• C. R-value measures moisture absorption.
• D. R-value measures the thickness of the insulation.

Answer: (B)

R-value is a measure of how well insulation resists heat transfer. It captures how much a material slows the flow of heat between indoors and outdoors. The higher the R-value, the greater the resistance to heat flow, so the insulation does a better job keeping warmth in during cold weather and heat out during hot weather, improving energy efficiency. This value depends on the material’s thermal conductivity and its thickness—more thickness or a material with lower thermal conductivity increases the R-value. It’s not about color, and it isn’t a direct measure of moisture absorption or simply the physical thickness, though thickness does contribute to the total resistance.