The _________ is a value used to indicate the ability of a material to resist heat.

The R value is a measurement that indicates the resistance of a material to heat flow. It plays a crucial role in assessing the insulating properties of products such as insulation, windows, and building materials. A higher R value signifies better insulating effectiveness, meaning that the material can prevent heat from passing through it more efficiently. This is particularly significant in construction, where energy efficiency and thermal comfort are essential concerns.

In contrast, while the U value measures the overall heat transfer through a building element (the lower the U value, the better the insulating properties), the K value typically relates to thermal conductivity of a material itself, and the V value does not represent a standard thermal resistance measure in building contexts. Understanding the R value helps builders and homeowners choose appropriate materials for energy-efficient buildings.