How to Read Windows Energy Performance Ratings
Today, consumers want high energy-efficient windows that allow them to reduce their heating or cooling costs and thereby their ecological footprint.
However, buying new windows can quickly become a complex process. How to ensure that these have a satisfying energy performance and how to understand the technical criteria entered on the labels?
To help you make an informed choice, here is the meaning of the main values evaluated for the energy efficiency of doors and windows:
U-factor: indicates the rate of heat transfer, in other words, the rate at which a building loses heat. The lower the value of the U factor is, the more efficient is the window.
Solar Heat Gain (SHGC): indicates the quantity of the sun’s heat that can pass through the window. In other words, how effective the window is at blocking the heat. The higher the value, the higher the solar heat gains.
Visible Transmittance (VT): indicates the amount of visible light passing through the window. The higher the value, the better the passage of light.
Energy Rating (ER): indicates the balance between U factor, SHGC and airtightness of a window. The higher the value, the more efficient the window.
There are also several standards regarding the airtightness and watertightness of the window that it is important to look at. Ask your epresentative for more information.
All of our windows meet high energy performance standards and are ENERGY STAR certified.