Making smart window choices starts with understanding these essential terms:
Awning -- A window with a single sash hinged at the top to open up and out from the bottom.
Casement -- A window with a single sash hinged on the left or right that opens out with a crank or lever. Casements provide maximum ventilation.
Double-hung -- A window with two sashes that bypass each other vertically when opened from the bottom and top.
Fixed glass -- A window that does not open. They come in a variety of shapes to combine with other windows. Large fixed windows are often called picture windows.
Gliding -- A window with two sashes that move horizontally in a common frame.
Picture window -- see Fixed glass.
Simulated divided light -- Any window with muntins affixed to the inside and outside of a panel of glass to simulate the look of true divided lights. Snap-on grilles can be removed easily to clean the glass.
Single-hung -- A window that features an upper and lower sash, but only the lower sash is operative.
Sliding -- See Gliding.
Specialty -- This term refers mostly to unusual shapes, such as triangular, round, half-round, and other nonstandard configurations, including bow and bay windows. Most are fixed-sash (inoperative) and are included to create architectural interest.
Tilt -- A double-hung window with sashes that tilt for cleaning.
True divided light -- Any window with multiple individual planes of glass assembled in the sash using muntins.
Pick a window that has the look you want inside and outside the house.
Your new windows should let in the light, not bad weather, and be easy to operate.
When choosing new bedroom windows, keep in mind that many casement and awning windows don't meet building code requirements for egress windows, which must provide passage in the event of fire.
Argon -- A gas injected between layers of glass to increase insulation. (Argon insulates better than air.)
Dual-glazed -- A window with two panes of glass, with air or argon gas in between the layers for insulation.
Jamb -- Each side of a window's frame.
Low-E (low-emissivity) -- A coating applied to glass to reflect heat and harmful UV rays.
Muntin -- A strip used to separate glass into multiple lights. (Vertical strips between panes are known as mullions.)
Pane -- The term for the glass part or parts of a window.
R-value -- A window's resistance to heat loss or gain. The higher the value, the better.
Sash -- The framework of the window that holds the glass.
Sill -- The bottom of the window frame.
Trim -- Any decorative, nonessential parts of a window.
Triple-glazed -- A window with three panes of glass, with air or argon gas in between the layers for insulation.
U-value -- The amount of heat escaping through a window. The lower the value, the better.