R-Value
Last Updated: May 30, 2024
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R-Value
R-Value
Share via E-mailR-value is a measure of thermal resistance, indicating how well a material can resist heat flow. It is expressed in units of ft²·°F·hr/BTU. A higher R-value signifies better insulating properties, which contribute to increased energy efficiency and reduced heating and cooling costs.
When R-value is used
R-value is used to evaluate the insulating effectiveness of various building materials. It is needed when assessing the energy efficiency of insulation materials used in walls, roofs, floors, and ceilings. By choosing materials with higher R-values, homeowners and builders can improve thermal insulation, leading to lower energy consumption and more comfortable indoor environments.
Difference between R-value and U-value (U-factor)
While R-value measures thermal resistance, U-value (U-factor) measures the rate of heat transfer through a material. Essentially, U-value is the inverse of R-value. A lower U-value indicates better insulating properties. R-value is commonly used for insulation materials, whereas U-value is more applicable for windows and doors.
U-value can provide a comprehensive measure of the insulating performance of entire window and door systems, taking into account the frame, glass, gas fill and low-E coatings. Lower U-values in windows and doors signify better insulation, which helps minimize heat loss in the winter, contributing to a more energy-efficient and comfortable living environment.
