Suitable for colonial homes and more traditional houses, double hung windows are about as time-honored as you can get. Robert Hooke (1635-1703), then the surveyor for the city of London, invented the first double-hung or sash window during the 17th century. Because of its classic look and simple design, it became the most popular window of 18th-century America. About.com has this to say about double hung windows:
The double-hung window is the most common style of window available. Most likely, you have seen a double hung window and not even known what it was called: it consists of two window sashes (i.e., panes of glass), one on top, one on the bottom.
Please note that double hung window should not be confused with double-glazed window, a method of sandwiching two sheets of glass with an air barrier in the middle.
Before, most windows were in casement style. These were smaller, however, as the available hardware at the time couldn’t support the weight of a large pane when opened because of the hanging design. With the double-hung window, movement became restricted to a simple up and down motion. It also started the use of a counterweight system for support, which expanded the window size range.
These weren’t considered highly efficient until recently, however. Gaps around the frame would let in cold air and it would rattle constantly in the frame as a result of wood drying out and shrinking over time. Fortunately, double-hung windows became improved due to advances in materials and workmanship.
Sash windows in Maine and other areas have become quite versatile as well, available at local home depots and provided by Renewal by Andersen Window Replacement. For instance, when applied with a fixed sash held tight to the ceiling, they create open and airy porch-like indoor spaces.
From creating detail and scale to allowing light to enter, double-hung Renewal by Andersen windows in Maine are now able to achieve the best of both traditional and modern styles. It’s no surprise that many are now integrating these windows in their homes.
(Article Excerpt from What is a Double Hung Window homerenovations.about.com)