TERM        DEFINITION

Astragal            The center member of a double door, which is attached to the fixed or inactive door panel.

Awning window

                        A window that has a single sash in which the bottom of the sash swings outward.  Awnings are typically from the pane of a wall & are good at keeping rain out even when open.

Bay window     A composite of 3 windows usually made up of a large center unit and 2 flanking units, typically there are 30 or 45 degree angles to the wall.  A bay window refers to the angle of departure from the pane of the wall.  Bays are tied into the overhang or on some a roof must be constructed above them

Between-The-Glass-Window Fashions

                        Blinds, fabric shades & grilles tucked between panes of glass.  Protected from dust and damage.

Bow window    A composite of 4 or more window units in a radial formation.  Typically at a 10 or 15 degree angle to the wall.

Brick mold       Exterior casing around a wood window or door through which nails are driven to install the unit.  Covers the gap between the frame & masonry opening.  In some cases, siding is installed up to the edge of the brick mold.

Casement window       

                        A window unit in which the single sash is either fixed or opens outward to the left or right.  Casements are generally taller that hey are wide.  They also offer complete ventilation as the entire sash opens.

Casing              Exposed molding or framing around a window or door, on either the inside or outside, to cover the space between the window frame or jamb & the wall.  They come in a wide variety of profiles & sizes

Design pressure

                        The pressure a product is designed to withstand.  This value is a measure of a product’s capacity to withstand the forces of wind loading, in both positive and negative directions, while it is closed & locked.

Dormer            A projection through the slope of a roof for a vertical window.

Double-hung window

                        A window until that has two operable sashes which move vertical in the frame.  A counterbalance mechanism usually holds the sash open or closed.  Many tilt in for easy cleaning.

Drip cap           Horizontal molding to divert water from the top of a window until so water drip beyond the outside of the frame.  May be metal or wood.

ENERGY STAR®

                        A government-backed program helping businesses & individuals protect the environment through the use of high-efficiency products. ENERGY STAR® qualifying products, such as windows and doors, mean these items useless energy, save money and help protect the environment.

Extrusion          A form produced by forcing material through a die.

Fenestration      An architectural term referring to the arrangement of windows & doors in the wall.  From the Latin word, “Fenestra”, meaning window.

Fixed                Non-venting or non-operable.

Flashing            A thin strip of metal or synthetic material that diverts water away from a window or door.

Frame              The combination of head, jambs and sill to form a precise opening in which a window sash or door panel fits.

French hinged door

                        A hinged door normally with wider stiles and rails but having panes constituting all or nearly half of its surface area.

French sliding doors

                        A sliding patio door, which has more substantial (wider) panel frame members giving it the look of French hinged doors.

Glazing             The process of applying or installing glass into a window sash or door panel.  Also refers to the type of glass used in the process.

Glazing stop      A molding around the interior or exterior of a window sash or door panels holding the glass in place.  Also called a glass stop.

Grille (Grilles)

                        Wood, plastic or metal dividers (grilles, grids, bars) designed for a single light sash or panel to give the appearance of muntins in a multi-light sash or panel.  These can be removable or fixed.  Also called Muntins.

Grilles-Between-The-Glass (GBG)

                        Grilles permanently installed between the panes of the insulating glass.

Head                The main horizontal member forming the top of the window or door frame.

Header             A horizontal framing member placed over the rough opening of a window or door to prevent the weight of wall or roof from resting on the window frame.

Hopper Window

                        A window unit in which the top of the sash swings inward.

Insulating glass (IG)

                        A combination of 2 or more panes of glass with hermetically sealed air space between the panes of glass.  This space may or may not be filled with an inert gas, such as argon.

Jamb                The main vertical members forming the sides of a window or door frame.

Jamb liner         The track in single-hung or double-hung window frame jambs on which the sashes slide.

Knocked down (KD)

An unassembled window or door unit.

Meeting rail      The bottom rail of the upper sash & the upper rail of the lower sash on a double or single-hung window where the lock is mounted which meets when closing.  Also known as Meeting Rail & Lock Rail & Check Rail.

Masonry opening

                        The space in a masonry wall left open for windows or a door

Mullion             A wood, metal, or vinyl part used to structurally join to window or door units.

Muntin              Applies to any short or light bar, either vertical or horizontal, used to separate glass in a sash into multiple lights.  Also called a window pane divider or grille.

Muntin Bar       Any small bar that divides window or door glass.  Also called a grille or windowpane divider.

Pane                 A framed sheet of glass within a window or door frame.

Panel                Usually refers to the separate panel, or panels in a door frame.  A panel may be operable or stationary.

Parting stop      A narrow strip, either integral or applied, that holds a sash or panel in position in a window or door frame.

Replacement Double-Hung Window

                        A fully assembled double-hung that slides easily into the existing sash pocket of your old double-hung with no damage to wallpaper, paint, or plaster.  For use in replacement applications only.

Rail                  The horizontal top & bottom members of a window sash or door panel.

Rough opening

                        The framed opening in a wall into which a window or door until is to be installed.

Sash                 A single assembly of stiles & rails made into a frame for holding glass

Sash Cord        A rope or chain which attaches to the sash & balance system of a single-hung or double hung window

Sidelights        A fixed frame of glass beside a window or door

Sill                    The main horizontal member forming the bottom of the frame of a window or door

Simulated

    Divided

    Light             Grilles permanently bonded to the interior & exterior of the insulating glass simulating a divided light appearance

Single

   Glazing          Single thickness of glass in a window or door

Single-hung       A double-hung type of window in which the top sash is fixed or inoperable

Sliding Patio  Door      

Patio door in which a vent panel moves horizontally on a track system past a fixed panel

Solar Heat Gain Coefficient (SHGC)

                        A measure of how effective a window or door is at keeping out solar heat.  It is calculated by taking the amount of solar heat that enters a room through a window or door (center glass), divided by the amount that is actually contacting the exterior of the unit.  The lower the value, the better the unit keeps out solar heat.

Sound Transmission Class (STC) Rating

                        Measures the amount of noise reduction that can be achieved with a given product.  A noise reduction of 10 decibels represents cutting the noise level in half, as interpreted by the human ear.  So a rating of 25 means that the product reduces the outside noise by approximately 25 decibels, cutting the noise in half 2-1/2 times, or cutting it by over 80%.

Stile                  The vertical members of a window sash or door panel.

Stool                An interior trim piece on a window which extends the sill & acts as a narrow shelf.

Stop                 A molding used to hold, position or separate window parts

Tempered glass

                        Glass manufactured to withstand greater than normal forces on it surface.  It is approximately 5 times stronger than annealed glass.  When it breaks, it shatters into small pieces to reduce hazard.

Transom           A small window that fits over the top of a door or window, primarily for additional light & aesthetic value.

U-value            The arte of heat transfer through a window, door, or skylight (center-glass).  The lower the U-value, the better the insulating properties of the unit or glazing system.

R-Value           Resistance to thermal transfer or heat flow.  Higher R-value numbers indicate greater insulating value.  It is the inverse of the U-Value (R=1/U)

Round top        A generic term referring to any of a variety of window units with one or more curved frame members, often used over another window or door opening. Also known as Round Top or Half Round.

Cladding           An aluminum or vinyl material bonded to the exterior of some windows.

Oriele               A double-hung window in which the upper sash is shorter than the lower sash.

Vent panel        The panel that moves horizontally on a sliding patio door.

Vent unit           A window unit the opens & closes.

Weatherstrip     A material of device used to seat the openings, gaps of venting windows & doors to minimize water & air infiltration.

Windload         The pressure, positive or negative on an external surface of a building caused by the direct action of the wind.