Energy Efficient Windows

Cooling Season Savings

In climates that mainly require cooling, windows have represented a major source of unwanted heat gain. In recent years, windows have undergone a technological revolution. It is now possible to significantly reduce solar heat gain and improve comfort while providing clear views and daylight. The graph below illustrates the significant savings in cooling season costs associated with improved windows for a house in a cooling-dominated climate. In warm regions, this means that high performance windows can face into the sun if desired without great energy penalties -- although shading techniques remain important.

Summer Thermal Comfort

High performance windows with new glazing technologies not only reduce energy costs but make homes more comfortable as well. In summer, strong direct sunlight strikes people and interior surfaces, creating overheating and discomfort. Windows with low solar heat gain coefficients (shgc) will reduce the solar radiation coming through the glass and associated discomfort. Low solar heat gain low-E glass (spectrally selective) reduces heat gain while still providing sufficient light and view.

Increased Light and View

Daylight and view are two of the fundamental attributes of a window. Unfortunately, windows are also the source of significant solar heat gain during times when it is unwanted. Traditional solutions to reducing solar heat gain such as tinted glazing or shades mean that the amount of light is reduced as well. New glazings with low-solar-gain Low-E (spectrally selective) coatings can provide better solar heat gain reduction than tinted glass, with a minimal loss of visible light. This also means that views can be clearer and unobstructed.