Double Hung windows offer a very traditional look to any home with the added features of energy efficiency and easy cleaning and maintenance. The double-hung window is perhaps the most familiar window type. It consists of an upper and lower sash that slide vertically in separate grooves in the side jambs. This type of window provides a maximum face opening for ventilation of one-half the total window area.
Each sash is provided with springs, balances, or compression weather stripping to hold it in place in any location. Compression weather stripping, for example, prevents air infiltration, provides tension, and acts as a counterbalance. Multiple layers of weather stripping and a sloped sill aid in water control and energy efficiency.
No more squeegees and ladder climbing to reach the window. The top and bottom sash both operate and pivot towards the interior for easy cleaning and maintenance. The operating window sashes offer a wide range of ventilation combinations for controlled air circulation.
One very important feature is the balance system holding each sash in any position. Age and manufactioring can varry quite a lot, lessing the stability of the windows.