Glossary of Window-related Terms


Argon — A non toxic gas used in insulating glass units to reduce heat and cold transmission.

Awning Window —A window style with a top-hinged sash that swings out at the bottom.  The window is good for a rainy day because it can remain open.

Bay Window (bench model) —A window style that has a middle picture unit with two windows on the sides that are usually at 30, 45 or 90 degree angles.  This addition does not add floor space, but acts a bench as it protrudes from the outside wall of the house up to 2 feet.

Bay Window (floor model) — A window style that has a middle picture unit with two windows on the sides that are usually at 30, 45 or 90 degree angles.  This model extends the floor of the room out up to 24" creating more floor square footage in the room.

Bow Window — A window style consisting of five or six individual windows set in a curved profile.   This model extends the floor of the room out up to 24" creating more floor square footage in the room.

Brickmould — It is the finishing piece furthest out on your window (picture frame shape) which surrounds and is attached to the window frame. 

Capping — A pre-finished aluminum section which is custom bent on site to cover any exposed wood so that it is maintenance free.  It comes in many colours.

Casement window —A window style that opens like a door.  it is side-hinged and can be ordered to open either left or right.

Casing— Exposed moulding or profile around the inside of a window or door.  Casing covers the space between the window frame or door jamb and the rough opening in the wall.   It also covers up the spray foam that has been put into this space.

Caulking —A maintenance-free material that is placed over top of another material to seal it from moisture and air penetration.

Cladding — A maintenance free material that is placed around the exterior perimeter of the new window for added performance and aesthetic appearance.

Condensation —The transformation of gas to a liquid form.  Warm air can hold more water vapour than cold air.  When warm air cools, its ability to hold water vapour reduces proportionately.   Excess moisture then condenses on the warm side of the glass.

Door slab — The opening part of a door.

Double glazed (duo pane) — An insulated glass unit consisting of two panes of glass with a single air space held together by a spacer bar and sealants.

Double Hung — A window style where the top window sash slides down or the bottom sash slides up. 

Egress Window — A window  designed to meet certain measurements specified by the Alberta Building Code to allow for a person or firefighter to climb in or out in case of an emergency, such as fire.

Energy Rating (ER) - The value developed by the Canadian Standards Association (CSA) to compare overall thermal performance of a window, based upon its glazing and frame material.  The higher the ER number the better the energy performance (numbers range from 0-40).

Energy Star for Windows — A federal government energy efficiency program sponsored by Natural Resources Canada.

Fascia — A horizontal piece of material that runs along the roof line and meets up with the soffit on the underside.  Eavestrough sits over top of the fascia.

Frame — The part of the window or door made up of the head, jamb and sill that houses the sash or glazing units.

Full Frame Replacement — where the entire existing window is removed and a new one is installed.

Glazing — Installation of glass into a window or door frame.   Also refers to various types of glass.

Grilles ( or Muntin Bars) —Decorative inserts located on or between the glass to simulate a true divided light look. 

Head — The horizontal frame member at the top of a window or door.

Horizontal Slider — A window style with a fixed sash and a sash that slides sideways or horizontally.  It is a good choice when choosing a window that is going into a bedroom and has to meet egress regulations in local building code.

Insert Window — Installation of a new window frame inside an existing older window frame.

Insulated Glass unit (IG/IGU) — A combination of two or more pieces of glass, factory-sealed using a spacer bar and sealants.  Typically referred to as dual or tri-pane units.

Jamb — the upright or vertical members of a window or door frame.

Laminated Glass —Two or more sheets of glass with an inner layer of transparent plastic to which the glass adheres if broken.  Used for enhanced safety, security and sound reduction.

Low-E — A glass type consisting of low-emissivity coating on one side.  used to reduce heat loss or heat gain dependent upon the Low-E selection.  Performance of Low-E units is often enhanced with the use of non-toxic gases such as argon.  Low-E glass is recognized for its significant contribution to reduction of energy cost. 

Muntin Bars (Grilles) —Decorative inserts located on or between the glass to simulate a true divided light look.

Picture Window — A window style that does not open.

R-Value —Resistance to thermal transfer or heat flow.  A higher R-value indicates greater insulating properties.  R-value is the inverse of the material's U-value

Rough opening —Opening in an exterior wall into which a window or door is installed.

Sash —The inner frame that opens in a window and also holds the glass.

SDL (simulated divided light) - A decorative bar mounted on the exterior and interior of a sealed unit that produces the visual affect of dividing glass into smaller units (like the old days when each unit was a separate piece of glass).  A shadow bar option utilizing metal grilles inside the glass unit further enhances the appearance towards true divided glazed units. 

Sidelights — A fixed unit or window joined to a door.  Available with venting options. 

Sill —The horizontal member at the bottom of a window or door frame.

Single hung — A vertical sliding window with an upper fixed unit and a lower sash which operates upward.

Soffit — Material running from the back of the fascia board to the wall, usually made of plywood, vinyl or aluminium.  Soffit is vented to allow air movement into the attic space under the roof.

Spacer bar —Used to separate the panes of glass in a sealed glass unit.

Sweep —The bottom portion of a door.  Sweeps are located on the bottom of the door slab and are adjustable to sit flush on the door sill.

Tempered Glass —Glass that is heat-treated to withstand greater than normal forces on its surface.  If broken, it breaks into small pieces to reduce cutting hazard.

Transom — A window unit attached to or combined with another window or doorframe unit.

Triple glazed (Triple Pane) — An insulated glass unit consisting of three panes of glass with two air spaces held together by two spacer bars and sealants.

Weather Stripping — A component of a window or door used to seal edges and gaps from exterior elements.