Panes

• The number of panes a window has refers to how many sheets of glass it has. Single-pane windows are just one layer of glass. Double- and triple-pane windows have two or three layers of glass separated by hermetically sealed air space between the panes to provide thermal and sonic insulation to the home.
  
  

Hung Windows

• The word "hung," when used with windows, relates to how the window opens. Hung windows open vertically.
  
  

Single vs. Double-Hung

• Only the lower sash is movable on a single-hung window. In the double-hung window, the upper and lower sash are movable and can both slide past each other.
  
  

Not Mutually Exclusive

• As far as these two types go, they are not mutually exclusive. A double-hung window can also have double panes and a double-pane window can also be double-hung.
  
  

Uses

• Double-pane windows help save money by reducing energy for heating and cooling. Double-hung windows are useful in being able to adjust which part of the window you desire open.