What is U-factor?
A U-factor or U-value is data to measure how much energy efficiency of your windows and doors by rating the combination of transmission of airflow, natural light, and heat gain coefficient. The lower the U-factor is, the more insulation your windows have, which means more energy efficient. The higher the U-factor is, the least energy efficiency is. U-factor is a key element when considering energy efficiency when buying new or replacement windows. U-factor has something to do with both glazing, sealing system, and frame material.
