Glossary of terms
(reproduction from North Star Windows and Doors)

Argon

An odorless, colorless gas used to replace air between glass panes. Being heavier than air, it slows heat loss.

Awning Window

A window hinged along the top. Rain can't get in when the window is open.

Balance

A spring or weight that holds the sash in any vertical location.

Bay Window

A combination of three windows that extends outward from the wall, generally joined at 30- or 45-degree angles.

Bow Window

A combination of three to five windows that extend outwards from the house to create a semi-circle or arc.

Cam Lock

The device that pulls the sash together when being closed.

Casement Window

A window hinged on the side and that opens outward like a door for superior ventilation.

Chambers

Tiny spaces within a North Star sash or frame that act like insulating air pockets and add strength.

Double-glazing

Two layers of glass separated by an air space.

Double Hung

A window with two operating sashes that slide vertically. Single hung has one moving sash.

Energy Ratings

A laboratory tests the energy-saving performance of a window and assigns a rating of how effectively the window controls energy loss.

Extruded screen

Not to be confused with roll-formed screens. Extruded screening is pressed through a form.

Fusion welding

Joining materials by melting with extreme heat. Separate parts take on the characteristic of one solid piece.

Grills

Decorative bars installed between panes to create the look of smaller panes.

Heat Gain

The amount of heat gained from sunlight. A low number on a performance test indicates a superior ability to block out heat.

Hopper

A bottom-hinged sash that opens inward.

Horizontal Slider

A window in which the sash moves horizontally.

J-channel

Extension on the outside of a new window that makes it easier to install siding.

Lite

A pane of glass.

Low-e Glass

Glass with a transparent coating that allows light to pass through but reflects infrared or heat.

Mullion

The vertical or horizontal bar connecting two or more windows.

Nailing Flange

An extrusion attached to the window and used to attach the unit to the opening.

Patio door

Glass door that slides on rollers to open and close.

Picture Window

Window with no moving sash.

R-value

Resistance. Measures how well a material impedes heat flow. Bigger is better with this number.

Sash

The frame around a pane of glass.

Super Spacer®

The silicone spacer around the interior perimeter of North Star windows. Keeps panes the right space apart and boost energy savings.

U-value

Measurement of heat transmitted through a material. The lower the number, the better the insulating quality.