Which rating is commonly associated with windows?

The commonly associated rating for windows is the U-rating. The U-rating measures the thermal transmittance of a window, which indicates how effective it is as an insulator. A lower U-rating signifies better insulating properties, meaning the window can retain heat in the winter and keep out heat in the summer, contributing to energy efficiency in buildings.

This rating is essential for consumers and builders to assess the energy efficiency of different window products and make informed choices regarding their installation in homes and commercial properties. Understanding U-ratings helps in compliance with energy codes and standards that aim to improve overall building performance and reduce energy consumption.