A sash window or hung sash window is made of one or more movable panels or "sashes" that form a frame to hold panes of glass which are often separated from other panes by narrow muntin bars into rows of three. Although any window with this style of glazing can be termed a sash, the term is generally used in reference to windows where the glazed panels are opened by sliding vertically in a track using a built-in pulley system. So typical of Edwardian, Georgian and Victorian architecture in Britain, the sash window is an essential component in your period scheme; framed by plush floor-to-ceiling curtains they make a beautiful feature.
If you are intending on having sash windows installed, choose a company that specializes in this type of window to be sure an authentic job. Although they may cost a little more, a specialist firm will better understand the subtleties involved in a successful re-creation such as the charming uneven quality of the glass or the correct proportions. Once installed, stay traditional in any treatments you may add in order to get the full effect of the window. If you are painting choose white or a subtle off-white to keep the window area bright, cheery and authentic. Adding brass handles and a period window seat will really add to the look, finally of course framing the whole area with curtains running the full length of the wall. In terms of curtain fabric, remain true to Victorian style and opt for a floral pattern in a bold or rich shade such as scarlet or plum.
As restoration work can be a little pricey, you may want to check the windows first to make sure you can’t fix any problems yourself as a simple sash or track repair can often restore a window to good working order. If a sash is temporarily stuck because of high humidity, a change of weather may correct the problem. If a sash moves reluctantly, clean out the sash tracks. If windows are completely stuck, chisel any dirt or large globs of paint from the channels, and then sand the track channels smooth with sandpaper wrapped around a wooden block cut to the correct size. It also helps to coat the surfaces of the channels with wax so the sash will move easily.