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Replacement window glossary letter "S"

Sash. The portion of a window that includes the glass and the framing sections directly attached to the glass, not to be confused with the complete frame into which the sash sections are fitted.

Screen. Woven mesh of metal, plastic, or fiberglass stretched over a window opening to permit air to pass through, but not insects.

Sealant. A compressible plastic material used to seal any opening or junction of two parts, such as between the glass and a metal sash, commonly made of silicone, butyl tape, or polysulfide.

Shade screen. A specially fabricated screen of sheet material with small narrow louvers formed in place to intercept solar radiation striking a window; the louvers are so small that only extremely small insects can pass through. Also called sun screen. Also, an awning with fixed louvers of metal or wood.

Shading coefficient (SC). A measure of the ability of a window or skylight to transmit solar heat, relative to that ability for 1/8-inch clear, double- strength, single glass. It is being phased out in favor of the solar heat gain coefficient, and is approximately equal to the SHGC multiplied by 1.15. It is expressed as a number without units between 0 and 1. The lower a window's solar heat gain coefficient or shading coefficient, the less solar heat it transmits, and the greater is its shading ability.

Sheet glass. A transparent, flat glass found in older windows, now largely replaced by float glass.

Short-wave infrared radiation. Invisible radiation, just beyond red light on the electromagnetic spectrum (between 0.7 and 2.5 microns), emitted by hot surfaces and included in solar radiation.

Sill. The lowest horizontal member in a door, window, or sash frame.

Sill track. The track provided at the sill of a sliding glass door. Also, the sill member incorporating such a track.

Simulated divided lights. A window that has the appearance of a number of smaller panes of glass separated by muntins, but actually is a larger glazing unit with the muntins placed between or on the surfaces of the glass layers.

Single glazing. Single thickness of glass in a window or door.

Single-hung window. A window consisting of two sashes of glass, the top one stationary and the bottom movable.

Single-strength glass. Glass with thickness between 0.085" and 0.100" (2.16­2.57 mm).

Skylight (operable or pivot). A roof window that gives light and ventilation.

Sliding glass door. A door fitted with one or more panels that move horizontally on a track and/or in grooves. Moving action is usually of rolling type (rather than sliding type). Also called gliding door, rolling glass door, and patio sliding door.

Sliding window. A window fitted with one or more sashes opening by sliding horizontally or vertically in grooves provided by frame members. Vertical sliders may be single- or double-hung.

Smart window. Generic term for windows with switchable coatings to control solar gain.

Solar control coatings. Thin film coatings on glass or plastic that absorb or reflect solar energy, thereby reducing solar gain.

Solar heat gain coefficient (SHGC). The fraction of solar radiation admitted through a window or skylight, both directly transmitted, and absorbed and subsequently released inward. The solar heat gain coefficient has replaced the shading coefficient as the standard indicator of a window's shading ability. It is expressed as a number between 0 and 1. The lower a window's solar heat gain coefficient, the less solar heat it transmits, and the greater its shading ability. SHGC can be expressed in terms of the glass alone or can refer to the entire window assembly.

Solar radiation. The total radiant energy from the sun, including ultraviolet and infrared wave lengths as well as visible light.

Solar screen. A sun shading device, such as screens, panels, louvers, or blinds, installed to intercept solar radiation.

Solar spectrum. The intensity variation of sunlight across its spectral range.

Sound Transmission Class (STC). The sound transmission loss rating of a material over a selected range of sound frequencies. The higher the number, the less sound transmitted.

Spectrally selective coating. A coated or tinted glazing with optical properties that are transparent to some wavelengths of energy and reflective to others. Typical spectrally selective coatings are transparent to visible light and reflect short-wave and long-wave infrared radiation.

Stile. The upright or vertical edges of a door, window, or screen.

Stool. The shelf-like board of the interior part of the window sill, against which the bottom rail of the sash closes.

Stop. The molding on the inside of a window frame against which the window sash closes; in the case of a double-hung window, the sash slides against the stop. Also called bead, side stop, window stop, and parting stop.

Storm windows. A second set of windows installed on the outside or inside of the primary windows to provide additional insulation and wind protection.

Sun control film. A tinted or reflective film applied to the glazing surface to reduce visible, ultra-violet, or total transmission of solar radiation. Reduces solar heat gain in summer and glare. Some can be removed and reapplied with changing seasons.

Superwindow. A window with a very low U-factor, typically less than 0.15, achieved through the use of multiple glazings, low-E coatings, and gas fills.

Switchable glazings. Glazings with optical properties that can be reversibly switched from clear to dark or reflective