ER Rating – Energy Star Program.

Each year thousands more Canadians change their homes over to the Ray-O-Max Window Powered Homes System. Our system has been recognized as the HIGHEST QUALITY ENERGY RATED WINDOWS ON THE MARKET TODAY! Windows with “Energy Ratings” as high as +18 will provide a lasting source of free energy for decades to come.

ER (Energy Rating) is a benchmark rating system adopted as part of the CSA A440.2 Standard of Canadian Building Code. It indicates the relative energy efficiency of windows (similar to Energuide ratings that compare household appliance energy consumption).

ER represents a single modeled performance rating for a window expressed in Watts per square meter (W/m2) based on standard window sizes and categories and average Canadian climactic conditions. It takes into account a window’s capacity to emit solar heat, its insulating capacity (R-Value), and its ability to resist air leakage. ER is derived from the formula:

ER (Energy Rating) =

• + “Solar” Power Glass
• energy transmission loss
• infiltration loss

ER ratings generally range from -50 to +15. A window with an ER of 0 is neutral in energy consumption – it contributes as much solar heat as it loses over a full heating season. A window with a positive ER contributes energy, while a window with a negative ER loses energy.

To learn more about energy efficient windows visit the NRC website.