Full frame glass values VS Center-of-Glass (COG) values:
Poorly insulated window frames or doors can transfer unwanted heat or cold into your home. That is why it is important to know the insulating capabilities of the entire window or door, not just the center of glass. Full frame R-value or U-factor will tell you how good your entire window or entry door is at insulating your home from the outdoor weather.
Measures the rate of heat transferred by a window or door and how well it insulates the home from the outdoor weather. The lower the U-factor, the better the insulating properties are.
R-Value is a standard measure of heat loss through the window or door. The higher the R-Value, the better it’s insulating properties are.
Solar Heat Gain Coefficient (SHGC):
Measures the percent of solar heat that actually enters through a window or door’s glass. The smaller the number of solar heat gain coefficient or SHGC, the better the window is at preventing solar heat from entering your home.
Visible Light Transmission (VT):
Measures how much light comes through the glass of the replacement window or door. The lower the number, the less visible light is transmittede.
Measures the percentage of damaging solar radiation that is blocked and not allowed to enter your home through the window glass. The higher the percentage of UV blockage, the less fading and damage to your furnishings and carpet the replacement window will allow.