If you live in a house that was constructed, before 1920, then it is highly likely that the original windows in your house are sash windows. Sash windows do require a high degree of maintenance as they are prone to rot; swelling in cold, damp weather; and shrinking slightly in warm, drier conditions, often resulting in rattling noisily whenever the wind blows more than a stiff breeze. Sash windows can also be quite difficult to paint as, even experienced painters, may paint over sashes causing the windows to stick and jam.
Owners of Victorian town houses or Georgian period houses will be understandably reluctant to replace original sash windows with modern style UPVC glazing. However, there are joinery companies which specialise in maintaining sash windows and eliminating some of the problems mentioned above, by adding draught proofing, new security locks and replacing broken sash cords. There are some advantages to having sash windows. They help to retain the character of an older building. They are relatively easy to clean from the inside by sliding the windows to different positions. They also allow good airflow through the house if the windows are open at the top and the bottom. Fresh air from outside enters at the bottom and and warmer air from inside leaves at the top.