Glossary

  • Air infiltration: Amount of air that passes between a window sash and frame. Measured in terms of cubic feet of air per minute, per square foot of rough opening. The lower the number, the less air allowed.
  • Argon gas: A non-toxic gas –odorless, colorless, and tasteless – which is six times denser than air. Used to replace air between glass panes (lite) to reduce temperature transfer.
  • Awning window: One or more sash hinged or pivoted at the top; swings out for ventilation.
  • Basement window: A sash unit, usually of the in-swinging awning or hopper type, used for basement or cellar sash openings. Any operating type may be tested as a basement window provided they are intended to be installed at or below grade to ventilate a basement or cellar area.
  • Bay window: Angled combination of three windows that project out from the wall of the home. Windows are commonly joined at 30- or 40-degree angles.
  • Bow window: Angled combination of windows in three-, four- or five-panel configurations. Windows are attached at 10-degree angles to project a more circular, arced appearance.
  • Casement window: Side hinged or pivoted, they contain one or more sash, glass panes and transoms in various combinations. They open inward or outward for ventilation.
  • Condensation resistance factor: Measure of the effectiveness of a window or glazing to reduce the potential for condensation. The higher the condensation factor, the more efficient the window or glazing system.
  • Desiccated matrix: Material used in insulating glass to absorb water vapor, which causes fogging.
  • Double glazing: In general, any use of two thickness of glass, separated by an air space, within an opening, to improve insulation against heat transfer and/or sound transmission.
  • Double-hung window: Two operable sash slides open vertically. The sash weight is offset by a counterbalancing mechanism mounted in the window.
  • Dual-action window: Sash tilts into the room from the top for ventilation and swings in from the side for cleaning of the outside glass.
  • Dual window: Configuration includes interior primary/exterior secondary window; exterior primary/interior secondary; and interior primary/exterior primary. The primary window protects the building’s interior from climatic elements; the secondary window is used in tandem with the primary window for energy conservation and acoustical enhancement.
  • Fixed window: Glazed frame or a fixed sash and frame installed into the opening and not operable; includes dual windows. Can be reglazed or replaced in the field.
  • French door: Hinged doors within an overall frame designed so that one or more of the panels are operable, swinging either to the inside or the outside.
  • Glazing: Process of sealing glass to the sash.
  • Greenhouse (garden) window: Three-dimensional, five-sided structure, with provisions made for supporting plants and flowers in the enclosed space outside the plane of the wall. Operating sash are available.
  • Hopper window, top-hinged: One or more sash hinged or pivoted at the bottom edge and projecting inward from the plane of the window at the top.
  • Horizontal sliding window: Single or two adjacent horizontal sashes in a sealing or weathering frame sash. Slide can be single, picture, bi-part center or double.
  • Jal-awning window: Multiplicity of top-hinge sash arranged in a vertical series within a common frame, each operated by its own control device which swings the bottom edges of the sash outward.
  • Jalousie window: Series of overlapping, horizontal louvers, which pivot simultaneously in a common frame. Upon opening, the bottom edge of each louver swings toward the exterior and the top edge swings toward the interior.
  • Laminated glass: Two or more pieces of glass bonded together with a plastic interlayer.
  • Low-E (emissivity) glass: Glass with a transparent metallic coating applied onto or into the surface. The coating allows short-wave energy to pass through, but reflects long-wave infrared energy which improves the "U," or heat transfer, value.
  • Picture window, slider: Horizontal sliding window with one or two moving sash located on one or both sides of a fixed panel to make up a two- or three-panel window.
  • Picture window, fixed: Non-operating window consisting of a frame and glass only.
  • Pivoted windows: Vertical or horizontal, they consist of a sash pivoted either at head and sill or at the jambs in the center of the main frame which reverses or rotates a full 360 degrees around its vertical and horizontal axis. When rotated 180 degrees, for the purpose of cleaning the outside surfaces, it also provides a weather seal.
  • Sash: Frame and glass.
  • Skylights: Windows placed at an angle in the ceiling or roof to make a room lighter and to appear larger.
  • Sliding door/patio door: One or more panels of glass within an overall frame designed so that one or more panels move in a horizontal direction. Some panels are sliding, some are fixed.
  • Solar heat gain: Percentage of heat gained from both direct sunlight and absorbed heat. The smaller the number, the greater the ability to reduce solar heat gain.
  • Tilt window: Hung window with sash that tilts into the room for interior washing.
  • Tropical awning window: One or more sash hinged or pivoted at the top and operated by one control device which swings the bottom edge of the sash away from the plane of the frame.
  • "U" factor: Hourly rate of heat transfer for one square foot of surface when there is a temperature difference of one degree F or the air on the two sides of the surface; also known as the "U" value or heat transmission coefficients.
  • Vertical sliding windows: Manually operated sash move vertically in relation to either fixed or similarly operating sash within a common frame. They’re held in one or more positions by mechanical means, instead of conventional, hung-window balancing devices