Energy Efficiency Window Services

The National Fenestration Rating Council (NFRC) provides consistent benchmark ratings on performance characteristics of different window and door brands, allowing you to compare different brands by the same fair standards. With MI Windows, we’ve invested time and money to provide consumers with certified performance data so you can be certain that our products will perform.

U-Factor ratings typically range between .20 and 1.20. The lower the U-Factor, the less energy you will use to heat your home.

Visible Transmittance, commonly referred to as VT, measures the amount of light that enters through your window. VT ratings typically range between 0 and 1. The higher the visible light transmittance, the more light is transmitted through your window.

A low Solar Heat Gain Coefficient, commonly referred to as SHGC, equates to less solar radiation admitted through a window. SHGC ratings typically range between 0 and 1. A lower SHGC rating means your home will remain cooler during the summer months.

Windows are tested for air infiltration to see if they allow air to pass through; a number rating of either 0.3, 0.2 or 0.1 is then assigned. The lower the number, the less drafts you’ll have in your home.

ENERGY STAR® performance requirements for windows and doors are tailored to fit the energy needs of the country’s different climate regions – Southern, Northern and Central. The ENERGY STAR® Climate Region Map gives you clear guidelines for determining which windows and doors will do the best job to help reduce heating and cooling costs in your region – and your home. To be sure, crosscheck your window selection with the Climate Region Map on each ENERGY STAR label. MI products meet performance requirements for all three regions.