The AFRC administer and approve comparative energy and related rating programs that serve the public and satisfy the needs of its private sector partners by providing fair, accurate and credible, user-friendly information on fenestration product performance.
If the products being purchased are AFRC approved then it is a fair comparison of products.
The measures of energy performance that relate to fenestration products are Solar Heat Gain Coefficient (SHGC), U Value and Visible Light Transmission. These three measures are of great importance when considering the design of a building to ensure comfort and energy performance of a building. The AFRC ensures that when you are comparing fenestration products that these measures are accurate and credible and an informed product choice can be made.
Solar Heat Gain Coefficient indicates the percentage of solar heat energy (direct radiation) that makes its way through the fenestration product under standard summer conditions. A lower value indicates less heat entering the building and thus a more energy efficient home if used in a warm climate or east or west elevation.
U-value is the measure of heat loss or gain due to differences in temperature/environmental conditions between the inside of the home and outside of the home. It is expressed in terms of WATTS per m2 per degree. A lower u-value indicates better insulating performances and thus a more energy efficient home.
Visible Light Transmission is the amount of light that is transmitted through a fenestration product, giving natural light to the inside of a building.