This section is from the book "The Principles And Practice Of Modern House-Construction", by G. Lister Sutcliffe. Also available from Amazon: How Your House Works: A Visual Guide to Understanding & Maintaining Your Home.
"'Let there be light' is said to have been the first command, and truly no command should ever stand before it or bar its way. Pure light purifies, destroys the organic poisons of spreading diseases, makes a cheerful countenance, gladdens the heart, causes the blood to flow quickly, brightly, and of natural hue. Plants, the universal purifiers for man, which take up his breath, which live on his breath, and which give it him back again in food-produce, sicken and die if they have no light, but live and grow, and grow rich in the waves of this their natural inheritance. 'More lightl more light!'
1 See Plate II., and Fig. 27. p. 81.
exclaimed the dying German poet Goethe. 'More light! more light!' exclaims the sanitarian, as he looks on the masses that arc dying prematurely in large dense populations, and, touched by Him ' who is clothed with light as a garment', sighs with them over their sorrows, sufferings, and oppressions".
The eloquence of these words of the late Sir Benjamin W. Richardson should not blind us to their truth. His description of the beneficial effects of pure light should be read as the message of science, and all engaged in building should ponder it carefully. The days of window-taxes are gone for ever, but some architects and builders seem to dread their rcimposition if one may judge by the sparseness of the windows in their buildings. Only those who have been compelled to pass a considerable part of their days in twilight rooms can appreciate the blessings of ample light and sunshine, or forcibly enough anathematize those who. carelessly or to suit a passing craze, design windows rather for external show than for internal brightness and comfort.
To pass from the glare of summer sunshine into the cool dimness of a long low room lit by a range of low narrow windows, all mullions and lead-lights, is a pleasant change, but the same room, in the days of cloud and rain, when books and embroidery are in our hands to while away the time, is a cheerless place till the lamps are lit. Doubtless, a range of low-mullioned windows is pretty, and in the country, where the daylight is not obstructed, rooms may be pleasantly illuminated thereby, but to employ such windows in towns, where the air is often choked with smoke and fog, is a sacrifice of internal comfort to external effect, of the householder's health and eyesight to the architect's fancy.
Carelessness and fashion, however, are not always responsible for insufficient illumination. The architect may honestly attempt to light a room properly and yet fail; perhaps trees intercept the light, or lofty buildings.
Several formulas for proportioning the area of windows to the size of rooms have been devised, but the difficulty of the problem is manifested by the dissimilarity of the rules.
Here are a few of them: - 1
Area of window
B+L/8 x B+L/4
(London Building Act, 1894).
1These rules have been reduced to the same terms for purposes of comparison: - B = breadth of room, L = length of room, and H = height of room. For a room measuring 15 ft. x 20 ft. x 12 ft. the rules give the following various estimates of window-space: - 1. 60 sq. ft.: 2. 38 sq. ft; 3. 36 sq. ft; 4. 30 sq. ft Some of the difference shown by these rules is due to a difference in measuring the windows; the three first are intended to give the area of the opening in the wall, while the last is the exposed surface of the glass, in other words, the net light-aperture. This golden rule may, however, always be observed, "Try to err on the side of light"; the glare of excessive light may be subdued by curtains and blinds, by tinted glass, by plants and screens, by low-toned decoration, but darkness can only be expelled by the main force of mason and bricklayer.
The desire for light, however, must not lead us to forget that there is such a sensation as cold. The more window-space there is in a room - other things being equal - the colder will it be in winter, and also the hotter in summer. Increase of window-space must be compensated in various ways if the comfort and healthiness of the room are to be maintained; double windows may be provided, or (better) double panes of glass separated by a small air-space; or (best of all) radiators, connected with some system of heating-apparatus, may be placed in the window-recesses.
Shortsightedness is often increased, if not altogether caused, by the in-sufficient or improper lighting of schoolrooms and workrooms. The importance of window-design is recognized by the Education Department. The principal windows of schools should be to the left of the scholars, but other windows are desired for diffusion of light and for through ventilation, and no room will be allowed in which one at least of the windows does not extend to the ceiling. In the design of hospitals, again, lighting is carefully studied, and the extension of the windows quite up to the ceiling is a cardinal point. Every house is at times school and workroom and hospital, and this fact should be borne in mind when the windows of the house are being designed.