Awning – A window that is hinged at the top of the sash, so that the bottom of the sash can swing open to the exterior of the building.

American Architectural Manufacturers Association (AAMA) – The American Architectural Manufacturers Association or AAMA sets all performance standards, product certification and educational programs for the window industry. When a product passes AAMA tests, you can expect long and reliable service as long as the window is installed and maintained correctly.

Aluminum – A malleable metallic element that has good electrical and thermal conductivity, high reflectivity, and resistance to oxidation.

Balances – A system used in tilt double-hung or tilt single-hung units that makes it easy to open and close your windows.

Bay – A stunning picture window combination that extends outside the house and is flanked on either side by operating casement of double-hung tilt windows placed at 30, 45, or 90 degree angles. Available with head and seat boards.

Casement – A window that is hinged on one side, allowing the window to swing open to either the right or the left.

Casement Window – A window that opens from the side like a door. Historically, casements were the first working windows. They were strategically placed throughout a house to capture breezes and direct them through the rooms. Screens are hung internally to prevent dirt and insects from entering the house.

Condensation – Condensation occurs when excess humidity in warmer air is released in the form of water droplets onto a colder surface such as a pane of glass.

Door Rollers – Two sets of tandem steel wheels with ball bearings for smooth operation. Usually found on sliding patio doors.

Double Glazing – Two panes of glass separated by an air-space to form insulating glass.

Double-Hung Window – A window with two sashes, upper and lower, that slide vertically past each other.

Extrusion – A form produced by forcing material through a die.

Eyebrow – Round top window consisting of a partial radius head. Typically used above a tilt, casement window or French door.

Fenestration – The placement (or arrangement) and design of the windows and exterior doors of a building. In Greek architecture, windows began as simple openings in temples. These openings began to contain glass in the 13 th century, when clear glass was available for buildings such as Westminster Abbey. Another important shift in fenestration occurred in the 20 th century when large windows became important components in commercial buildings.

Frame – The assembly of structural members (head, sill, jambs) used to fasten a window sash or a door panel to a structure.

Glazing – Refers to both the type of glass used in a window and the actual process of installing glass in the window frame or sash.

Glazing – The process of mounting glass into windows and doors. Glazing also refers to the lowest quality of plate glass. The purpose of glazing is to retain the glass adequately under the design load, provide an effective weather seal, prevent loads or pressure points on the glass resulting from building movement, prevent glass-to-metal contact, and minimize glass breakage from mechanical or thermal stress. An insulating glass (IG) unit is two glass panes separated by a spacer and sealed. IG glass is offered in clear (no special coating) and high performance, which has a tinted, low-emissivity coating for exceptional energy efficiency.

Hardware – The locks, cranks and hinges on windows and doors used to make them operational and secure.

Head – The horizontal piece that makes up the top of a window or door frame.

Jamb – The vertical (left and right) portions of a window or door frame.

Lockset – The complete lock system comprised of the lock mechanism, knobs, keys, plates, strikes and other accessories.

Low E Glass – Low E stands for “low emissivity”, a microscopic coating on glass that helps keep your house warmer in the winter and cooler in the summer.

Low-Emmisivity – Low-e glass is manufactured by depositing a microscopically thin, transparent metal or metallic oxide layer on the glass. Low-e coatings reduce radiant heat loss, and can reduce the passage of UV rays. Use of heat-resistant (or absorbing) glass begain in the 1950s, as did the use of reflective (or mirror) glass.

Meeting Rail (Check Rail) – The horizontal members of a tilt double-hung sash that meet, and the vertical members of a slide/by sash that meet.

Mulled (Mulling) – Joining two or more window or door units together to form combinations. The joint is finished with an exterior mull cap or mull trim.

Muntin Bars – The narrow horizontal and/or vertical grilles in a True Divided Lite unit that separate individual lites, or panes, of glass.

Muntin – The individual pieces of a decorative grid that help divide a window opening into smaller sections.

Pane – A single piece of glass within a window or door.

Picture Window – A fixed window – typically of a large size in relation to adjacent windows.

Picture Window – A large stationary window used to capture wide views of exterior landscape. Can be combined with other functional windows such as a double-hung or casements, and/or topped with direct-set or awning windows for enhanced views.

Rails – The horizontal members of the framework of a window sash or door panel.

Rough Opening – The opening in the wall where the window or door is to be installed, slightly larger than the size of the unit to allow squaring.

Round Top (Circle Top) – Direct set quarter circles, half circles, half ellipses, arch tops, ellipses, full circles and gothic arch top windows that can be used alone, in combination or stacked above another window or door.

R-Value – A measurement of how much a material resists heat transfer. A higher R-Value means a greater insulating effect and a lower rate of heat flow.

Safety Glass – See “Tempered Glass”.

Sash – The top and bottom horizontal rails and vertical left and right stiles that house the window glass.

Side Jamb – The vertical left and right members of a frame.

Sidelite – A narrow fixed or operating sash consisting of either steel or wood stiles and rails, glazed with clear or decorative glass and matching the sight lines of the entry door. Sidelites are typically mulled to the entry door on one or both sides.

Sill – The bottom of the frame of a window or door.

Simulated Divided Lite – Windows with grilles adhered to the interior and exterior of the window glass, in a variety of decorative options, to simulate the look of True Divided Lite.

Sliding Patio Door – Up to four glass door panels that slide on tracks giving fast, easy access to the outdoors.

Slider Window – A window with a sash or sashes that move horizontally.

Solar Heat Gain – Solar Heat Gain Coefficient (SHGC) measures how well a product blocks heat caused by sunlight. The SHGC is the fraction of incident solar radiation admitted through a window, both directly transmitted and absorbed, then subsequently released inward. SHGC is expressed as a number between 0 and 1. The lower a window's SHGC, the less solar heat it transmits.

Spacer – An anodized aluminum bar used to separate the panes of glass in an insulating window.

Tempered Glass – Float glass that is heated and then cooled rapidly to make it several times stronger than annealed glass. Standard in all Weather Shield doors, tempered glass is safer than annealed glass because when it is broken it falls into pebble-0like pieces without sharp edges.

Tilt – Both sash of this window slide up and down to allow air into the room, as well as tilt into a room for easy cleaning on both sides.

Transom – A window stacked above another window or door.

U-Value – A measurement of how much energy a material conducts. The lower the U-Value, the greater the insulating effect.

Visible Transmittance – Visible Transmittance (VT) measures how much light comes through a product. The visible transmittance is an optical property that indicates the amount of visible light transmitted. VT is expressed as a number between 0 and 1. The higher the VT, the more light is transmitted.

Weatherability – Performance in various climates.

Weather Stripping – A strip of resilient material designed to seal the sash and frame members to reduce air and water infiltration.