Energy Efficient Numbers You Should Care About
Window numbers matter. Coldness and heat can come through any poorly designed window. That’s why it is important to know everything you can about your windows. Full frame window values versus Center-of-Glass (COG) values: Poorly insulated window frames can transfer unwanted heat or cold into your home. That’s why it is important to know the insulating capabilities of the entire window, not just the center of the glass. Full frame R-value or U-factor will tell you how good your entire window is at insulating.
U-factor measures how well heat is transferred by a window and can affect heating and air conditioning costs; the lower the U-factor, the better the insulating properties.
R-value is the standard measure of heat loss through a partition, such as a wall, window, or door; the higher the R-value, the better its insulating properties.
Solar Heat Gain Coefficient (SHGC)
Solar Heat Gain Coefficient measures the percent of solar heat that actually enters a building through a window. The smaller the number, the better the window is at preventing too much warmth from coming in.
Visible Light Transmission (VT)
Visible Light Transmission neasures how much light comes through the glass; the lower the number the less visible light is transmitted
UV Blockage measures the percentage of damaging solar radiation that is blocked and not allowed to enter your home. The higher the percentage, the less fading and damaging to your furnishings and carpet.