How do R-value and U-value affect building energy efficiency?

R-value and U-value play critical roles in building energy efficiency. A higher R-value (lower U-value) indicates better insulation, which reduces heat loss in winter and heat gain in summer. This leads to lower energy consumption and costs. Conversely, a lower R-value (higher U-value) indicates poorer insulation, resulting in increased energy consumption and costs. By selecting materials with optimal R-values and U-values, building designers and engineers can optimize energy efficiency and reduce environmental impact.