Windows affect the comfort of the family, both physically and psychologically. They are, moreover, a very important influence on the design and the structure of the house.

From a physical aspect, windows are expected to admit daylight in desired quantities and to provide a means of ventilation. At the same time, cold air leakage around window openings in winter and heat gain through glass in summer must be minimised.

From a psychological aspect, windows are expected to provide an outward view, whilst maintaining the necessary provisions for privacy.

Windows should be acceptable in architectural appearance, both on the inside and the outside of the house. They should; moreover, be of such measurements that they can be used efficiently with other building materials.

Selection of the types and sizes of windows and their placement depend on how the various windows are to be used. These requirements frequently are at cross-purposes, for example: the placement and size of a window for maximum daylight may not coincide with placement and size for maximum ventilation or for enjoyment of a view. A compromise can be reached, however, by careful planning.

Irrespective of these guidelines, the final sizes and location of any window must conform to the building code for any specific area and the Building Act By-Law will govern all such decisions.