Search our window construction terminology page and explore glossary terms related to energy efficiency and performance. The following is 1 of 4 pages on our section dealing with window terminology. For a visual, refer to our anatomy of a window.
Window Construction Terminology
Air Infiltration
Ahe amount of air that leaks through the edges of a frame when it is closed. This calculation is represented as cfm/sf or cfm/sq ft, which translates to ‘cubic feet per minute per square foot’.
Condensation Resistance Factor (CRF)
An indicator of how resistant a window is to condensation. Higher numbers indicate better resistance.
Conduction
The amount of energy that is transferred between materials that are in direct contact with one another.
Convection
The amount of energy that is transferred by air circulation between surfaces.
Energy Star®
The Energy Star system that has been set up by the government to help consumers determine which products provide more energy efficiency.
Heat Absorbing Glass
Glass that is tinted in order to absorb heat and light and reduce glare. Learn more on replacement glass.
Low-E Glass
Also known as low emittance glass, it is glass which has a specialized coating to reduce radiant heat gain and create better energy efficiency.
Additional Window Construction Terminology
National Fenestration Rating Council® (NFRC)
An organization that certifies energy ratings for windows, doors and skylights.
R-Value
An indicator of a window’s insulating properties and resistance to heat transfer. The higher the value, the better it is at insulating against heat transfer. This value is the inverse of the U-factor.
Radiation
The heat producing spectrum of the rays of the sun.
Reflective Glass
Coated glass that can reflect the heat and light of the sun, reducing the amount of heat transfer and glare.
U-Factor
An important replacement windows ratings that indicates a window’s heat transmission (indicative of energy efficiency). The lower the U-factor, the better the insulative properties of the window. This value is the inverse of the R-value.
Ultraviolet Light
The short wavelengths of light that can cause fading.
Visible Transmittance
VT – a measurement of the percent of visible light that penetrates through a window.
Warm-Edge Technology
The use of spacers that have low conductive properties near the edge of insulated panes of glass. This further reduces the amount of heat transfer and increases energy efficiency.
Wind Load
The measurement of force caused by moving air against a surface.
Related Topics
Components Terminology
Frame Terminology
Installation Terminology
