To ensure even distribution of the greatest amount of daylight within a room, consider the following tips when designing your home:

• Provide glass areas in excess of 20% of the floor area of each room. This is a general rule of thumb. Most building codes recommend that the glass area be not less than 10%, but much more is desirable to meet daylight requirements on cloudy days. On brighter days, the amount of light can be controlled by interior and exterior shading devices.
• Place the main window area toward the north, except in hot climates where a southern orientation is favoured in order to limit heat from the sun. The north sky is considerably brighter than the south sky. A northern exposure permits the maximum amount of daylight and also the greatest amount of solar heat in winter.
• Group window openings in the wall to eliminate undesirable contrast in brightness. Provide one large opening on a wall instead of several small ones to do away with dark areas between openings.
• Select the window shape that gives the desired distribution of light within each room. For a broad, shallow distribution of light, use short, wide windows. Tall, narrow windows give a thin, deep distribution of light. Intensity of light is great near the window and then drops off rapidly and smoothly within a short distance.
• Place the window as high in the wall as possible to lengthen the depth of light penetration into the room. If possible, place the top of the window close to the ceiling. More sky is visible through the upper parts of the window than the lower, moreover, the overhead sky is brighterthan the sky at the horizon.
• Use windows in more than one wall for greater admission and better distribution of daylight.
• Do not specify corner windows or bay windows as a means to increase the daylight effectiveness of the window. The actual area of glass is greater and more costly than the effective daylight area obtained.
• Screen only those parts of the window that open for entilation. Full screens on a double hung window can absorb as much as 50% of the available daylight. Half screens absorb only 15%.
• Finish ceilings and walls (and even the floor if practical) in light colours to take advantage of light distribution made possible by reflection. Use flat or dull finishes. Furnishings, especially curtains, should also be light in colour.
• Mount curtains, shades and other window hangings above the top of the window and to the side of the window frame, in order to free the entire glass area and thus admit the greatest amount of light. Dark, heavy curtains hung over the sides and top of a window can reduce the available daylight. The practice of pulling window shades one-fourth ;or one-half of the way down results in loss of light at the rear of the room where it is most needed.

• Air moves because of differences in temperature or differences in pressure. In single storey homes, the movement of air because of differences in temperature is negligible. The placement of windows in these homes therefore, should be governed by movement of air due to pressure differences.
• A high pressure area is created when air strikes a building. Low pressure areas are created as the air moves over and around the building. Air flows into a home through openings in the wall against which the wind blows. The wall acts as a dam, causing the air pressure to build up. Air flows out of a home because of differences in pressure. It moves from high pressure areas inside the home, through openings to areas of lower pressure outside the home.
• To speed the movement of air within a room, the openings through which the air leaves the home should be larger than those through which it enters. Obstacles in the path of moving air cause it to change direction, thus slowing it down, i.e. trees, shrubbery or fences on the outside; partitions, walls, or furniture on the inside. Because the cooling effect of air in summer depends on its speed, obstructions which slow the movement of air should be kept to a minimum.
• The angle at which the air enters and leaves the room is the controlling influence on the pattern of air movement within the home. This angle depends on the location and type of window. Refer to the following tips to select and locate windows for the best ventilation.
• Provide ventilation openings in excess of 10% of the floor area of a room. This is a general rule of thumb. Most building codes have established minimums of 4-5% of the floor area, but just as large glass areas provide daylight for cloudy days, sufficient ventilation openings can offer relief on warm, sultry days.
• Locate the house and the ventilation openings to take full advantage of prevailing breezes. Do this by determining the high and low pressure areas as defined by the shape of the house – the walls which the breeze will strike and the walls around which the air moves. Allow for changing wind directions.
• Locate windows so as to effect the best movement of air across the room and within the level that occupants sit and stand. Do this by placing windows away from exterior corners and placing horizontal sliding, casement and awning windows in the lower part of the wall since these window styles cannot direct the movement of air downward.
• Plan landscaping, interior partitions, and furniture so they do not interfere with air movement. If possible, place the house so that existing buildings and hills do not divert the wind away from the house. Avoid setting trees, shrubbery and fences in the path of the breeze.