The type of window and the installation method used depends on the problem that is being overcome and the construction characteristics of the house. The following problem areas are presented and explained to help you understand the various directions your new window installations might take.
HEAT FROM SUN
Infrared rays of the sun coming through a window will create additional heat above the heat that is blocked out by the dual-pane windows. So where you have a southern or westerly exposure you may need a tinting to block out this heat. This measurement (SHGC) is different than the U-value (as explained under insulation).
QUANTIFYING
WINDOW INSULATION
SHGC – (Solar Heat Gain Coefficient). The measurement of blocking heat from the sun. Lower Values = Better blockage.

U-Value – the measurement of heat flowing through a window. Lower values = better insulation