Energy Efficient Windows

How to identify an energy-efficient window – 3 Key factors

U Factor
This measures the ability of a window to retain the heat in your home in the winter. The Lower the u value the better. A good number would be .30 or lower.

SHGC
This stands for solar heat gain coefficient. It measures the ability to keep the heat out in the summer. A good number would be .30 or lower. If the window faces south or west and gets a lot of Sun .20 to .26 would be preferred.

Air Infiltration
This is the most important number of all, if a window is leaky and lets in cold air in the winter, the U factor and SHGC are meaningless. Windows are tested with a 25 mph wind to see how much air leaks around the weatherstrip. It is measured in Cubic Feet per Minute (CFM). One cubic foot is equal to about 7 gallons of air, so if a window was leaking about 1 CFM it would let in over 7 gallons of air. The Industry considers .30 CFM energy efficient, but that is still over 2 gallons of air every minute, for every window in your house. Look for a window that measures somewhere between .01 CFM and .15 CFM. , that way you will not feel those cold drafts in the wintertime.

Energy-efficient glass reduces monthly utility bills. The replacement windows installed by ProBros Window & Door include some of the most advanced features available today. At the heart of our replacement windows is a technologically advanced glass called Low-E (low emissivity) glass. Low-E glass maximizes your home’s efficiency by reducing the amount of heat entering or escaping. Microscopically thin layers of oxidized metal are applied to the glass surface, allowing filtered light to pass through while reflecting most heat energy back to its source – an incredibly efficient way to reduce energy loss.