This particular Note is designed to inform Historic Scotland staff and others when considering proposals or requests to alter traditional sash and case windows or to replace them with windows of modern design.

By considering the range of performance standards currently applicable to any type of window and evaluating the performance of traditional sash and case windows against these standards this Note concludes that:·

• Traditional sash and case windows can provide modern standards of comfort and convenience·

• Many existing sash and case windows require no treatment other than good regular maintenance.·

• Where feasible, the upgrading of existing windows and the fitting of an effective weather stripping system is likely to provide the most cost effective solution to commonly occurring problems.·

• Straightforward double glazing of traditional sashes is not in itself a solution to most of the problems. Effective weather-stripping is essential if performance is to be substantially improved.·

• The provision of weather-stripping in conjunction with secondary internal windows will provide the highest standards of performance under all categories.·

• Safety and security requirements can be met by original windows supplemented where necessary by modern fittings.·

• Where replacement of original windows is unavoidable, and suitable off-the-shelf replicas are not available, initial costs of historically correct designs maybe higher than for other (unacceptable) types. However full life cycle costs in use for timber sash and case windows are likely to be less than for replacement windows of other types and materials.

In the case of listed buildings or buildings in conservation areas, listed building consent or conservation area consent should be required where works would involve a change in the appearance of the windows.