Window Replacement Terminology Everyone Should Know

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The team at Adler Windows has gathered and explained all the terminology you will want to know when entering in a window installation or replacement project. 

AAMA: American Architectural Manufacturers Association, a national trade association that establishes voluntary standards for the window, door and skylight industry

Air infiltration: Industry test that measures the amount of air leakage through cracks in the windows or doors

Apron: Decorative trim positioned directly underneath a window stool

Arch window: Four sided window unit with a curve at the top

Awning window: A window hinged at the top so the sash swings outward from the bottom

Backbedding: Material or compound used to seal the glass to a window sash

Balancer: Counter-weight mechanism to assist raising or lowering of a double-hung or single-hung sash

Bay window: Window consisting of three or more units that angle out beyond the wall

Brick mould: Exterior trim around the window frame traditionally used to attached the window to the wall

Casement window: A window hinged on either side – the sash opens horizontally opposite the hinge

Casing: Flat, decorative molding used on the interior perimeter of a window or door that covers the space between the unit and rough opening

Check rail: Located on double-hung windows where the bottom sash and top sash meet and the lock/keeper is mounted

Clerestory: Window located up high on wall; typically unreachable from ground level

Coil stock: Roll aluminum that is bent into shape to form a transition piece between the unit exterior and siding/trim

Condensation Resistance: Condensation Resistance (CR) measures how well a window resists the formation of interior condensation. CR is expressed as a number between 1 and 100. The higher the number, the more resistant to condensation formation.  Condensation Resistance ratings are determined under specific laboratory conditions. Actual condensation performance is a function of temperature, humidity and air movement as well as other uncontrolled, site specific factors

Double glazing: Use of two panes of glass in a window to increase energy efficiency and provide other performance benefits

Double-hung window: Venting upper and lower sash in a single frame that slide vertically past one another

Double-strength glass: Glass between 0.115 and 0.133 inch thick.

Drip cap: One piece aluminum or vinyl cover installed above windows/doors that directs water away from the top of the unit

Energy Star: A program sponsored by the U.S. Environmental Protection Agency that establishes minimum performance standards for windows to be recognized as energy efficient. Four different sets of standards for U-value and solar heat gain have been established for four different climate zones in the U.S. See the Association Directory for more information on the Energy Star Windows program. More stringent requirements are planned for 2015

Exterior trim: A decorative trim positioned around the exterior perimeter of a window

Fenestration: Arrangement of windows and doors on the elevation of a building

Fixed/Stationary: Non-venting or non-operable

Flashing: Water resistant material that directs water away from your windows

Frame: Outer structure of a window or door that holds the sash or panel in position

French casement window: Unit with two venting sash that open outward to provide a large center opening with no center post

Glazing: Glass in a window sash or door panel; the act of installing glass in a window sash or door panel

Glazing bead: Wood or vinyl pieces around the perimeter of the glass that covers the space between the glass edge and sash/panel

Gliding window/sliding window: Window with two sash, where one sash slides horizontally past the other

Green building: A movement in architectural and building circles aimed at creating structures that are occupant and environmentally friendly. Criteria such as sustainability, energy efficiency and healthfulness are considered

Grilles/Muntins/Dividers/Bars/Grids: Components used to simulate individual pieces of glass within a sash/panel

Insert window: A new window unit intended to be installed inside the frame pocket of an existing window

Insulating glass unit: Two or more glass panes that are sealed together to increase energy efficiency

Laminated glass: Layered glass that resists breakage and holds together when broken

LEED rating system: A “green building” rating system established by the U.S. Green Building Council. Currently applicable to new commercial construction and major renovations, the program is being expanded to include residential construction as well. LEED stands for Leadership in Energy and Environmental Design

Life-cycle analysis (LCA): An assessment of the environmental impact of a product that takes into account its entire lifespan. For a window or door, this would include energy
and materials used to manufacture, its energy savings contribution during its useful life, and its disposal and/or capacity to be recycled

Lift: Handle on the bottom of a double hung window that makes it easier to raise/lower the sash

Low-E glass: Glass with a low-emissivity coating that restricts heat loss

Mulling: Joining of two or more window or door units together; joint can run vertically, horizontally or both

Mullion: The vertical or horizontal joint between individual window or door units that form a combination

Multi-point lock: Lock that engages the sash or panel in multiple locations; activated by a single motion

Reinforced mull: Mull that uses a structural material (wood, aluminum, steel, LVL) to provide a stronger joint

Sash: Rail, stile and glass components joined together the form the venting capability of a window

Sill: Horizontal member that forms the bottom of a window or door frame

Single-hung: Double-hung styled window in which the top sash is inoperable

Triple pane: Glass construction consisting of three distinct layers of glass and two air-spaces

Vinyl: Polyvinyl chloride (PVC) material that is very durable and resistant to corrosion.

Questions? Contact one of our experts today and start your window installation project by scheduling our no obligation free consultation !