Glossary of Terms

Argon gas
an inert, nontoxic gas used in insulating glass units to reduce heat transfer
Balance covers
a snap in covering that conceals the balance system within the window frame helping to keep dirt and dust our of the chamber
Block and tackle balance system
the block and tackle system utilizes a high-density nylon pulley which is attached to a moveable block that travels up and down within a metal chamber and the tension from a heavy duty coil spring at the top of the block creates the proper resistance necessary for smooth operation of the window sash
Butyl
a rubber material that seals the glass to the spacer creating an airtight and water-tight insulated glass unit
Coved glazing bead
a contoured piece of vinyl that holds the glass in place within the sash and adds an elegant finished look
Fenestration
the placement of window openings in a building wall as one of the most important elements in controlling the exterior appearance of a building
Fixed lite
a pane of glass installed directly into non-operating framing members
Fixed panel
an inoperable panel of a sliding glass door or sliding window
Fusion-welded
the process of joining materials by melting them together with extreme heat (in most cases over 500°F) resulting in the materials combining into a one-piece unit
Glazing bead
a molding or stop around the inside of a window frame to hold the glass in place
Grids
optional horizontal and/or vertical lineals manufactured in a window to maintain the architectural style of a home
Jamb
a vertical member at the side of a window frame or the horizontal member at the top of the window frame
Krypton gas
an inert, nontoxic gas used in insulating windows to reduce heat transfer
Lift
handle for raising or lowering the sashes in an operable window
Low emissivity (low-E)
metal or metallic oxide layers deposited on a window glazing surface primarily to reduce the u-factor by suppressing radiative heat flow
Meeting rail
the part of a sliding glass door, a sliding window or a hung window where two sashes meet and create a weather barrier
R-value
a measure of the resistance of a glazing material or fenestration assembly to heat flow
Solar Heat Gain Coefficient (SHGC)
the fraction of solar heat loss or gain through a material or assembly
Spacer
an object placed between two or more pieces of glass which helps to maintain a uniform width between the glass and helps prevent sealant distortion
u-Value (u-Factor)
a measure of the rate of non-solar heat loss or gain through a material or assembly
Weatherstripping
material used to form weather-resistant seal around an operable sash