As long as there have been windows in buildings it has been recognized that they are a source of draftiness, heat loss or gain, migration of air contamination as well as their original purpose, to provide light and ventilation. Originally, windows were simply openings in the building envelope that allowed in light. They were closed with wooden shutters and covered with draperies to help keep out the cold. The advent of glass allowed for the development of window sashes that permitted light to enter, but kept out (some of) the cold when closed.
The first attempts to provide better energy efficiency and eliminate some of the draftiness were storm windows. Originally, these were simply wooden frames, glazed with a single sheet of glass, that were mounted over the exterior of the existing window. They effectively provided "double glazing" but no ventilation, so it
The first attempts to provide better energy efficiency and eliminate some of the draftiness were storm windows. Originally, these were simply wooden frames, glazed with a single sheet of glass, that were mounted over the exterior of the existing window. They effectively provided "double glazing" but no ventilation, so it