Glossary of Window Terms

AIR CHAMBERS - Small honeycomb spaces within the sash and frame which help to insulate and strengthen the window.

ARGON GAS - An odorless, colorless, tasteless, non-toxic gas which is six times more dense than air. It is used to replace air between the glass panes to reduce temperature transfer.

AWNING - A top-hinged window that swings outward for ventilation.

BAY - An angled combination of windows that projects out from the wall of the home.

BEVELED EXTERIOR - An extension of the vinyl frame that adds an aesthetically-pleasing dimension to the exterior of the window.

BOW - Similar to Bay, but the combination of windows has a more circular arced appearance.

CAM LOCK AND KEEPER - The mechanism which pulls sash together when placed in the locked position.

CASEMENT WINDOWS - Crank-out style windows, hinged on the side.

CONDENSATION RESISTANCE FACTOR - A measure of the effectiveness of a window or glazing system to reduce the potential for condensation. The higher the condensation resistance factor, the more efficient the window or glazing system.

CONDUCTION - Energy transfer from one material to another by direct contact.

CONVECTION - Heat transfer by currents that flow from a warm surface to a colder one.

DOUBLE HUNG WINDOWS - Windows that have an operable top and bottom sash.

DESICCATED MATRIX - A material used in insulating glass to absorb water vapor which causes fogging.

FUSION WELDED - Refers to frames and sash fused together with intense heat.

GLAZING - The process of sealing the glass to the sash.

KEEPER RAIL - The bottom horizontal section of the top sash that the keeper is fastened to. On sliders, the keeper rail is vertical.

LOCK RAIL - The top horizontal section of the sash that a cam lock is fastened to. On sliders, the lock rail is vertical.

LOW E (EMISSIVITY) GLASS - Glass treated with thin transparent coatings of metal oxide and silver for improved thermal performance. It reduces the penetration of ultraviolet rays to minimize fading of carpet and draperies.

MECHANICAL FRAME - Refers to frames fastened with screws.

MESH - Fabric, made of either fiberglass or aluminum, used in the making of screens.

MEETING RAIL - The point at which the horizontal sections of the top and bottom sash meet. On sliders, the meeting rail is vertical.

ORIEL - A single hung or double hung window with the meeting rail not located in the center of the frame. Most oriels have a 60/40 configuration.

PICTURE WINDOW - A window that has no moveable sash.

R VALUES - Resistance a material has to heat flow. The higher the R value, the greater the resistance.

RADIATION - Wave energy transmitted directly from one object to another through the atmosphere or through transparent or translucent materials. The energy radiated is either transmitted, absorbed or reflected, or a combination of all three.

SASH - The part of the window which contains the glass.

SLIDER - Window with sash moving horizontally instead of vertically.

U VALUES - Amount of heat transferred through a material. The lower the U value, the slower the rate of heat flow.

WINDOW WALLS - A line of Casement windows, or a combination of Casement and Awning windows.