For Designers

Providing Fresh Air

Windows provide the primary means to control air flow in most homes. People open windows to provide fresh air, ventilate odors and smoke, dissipate heat and moisture, and create air movement on hot days. While exhaust fans and central air systems can mechanically ventilate a room, opening a room to the outdoors is perceived as more direct and natural. Architects have often found that people will insist upon having operable windows even though they may rarely open them. There seems to be a strong psychological need to know that a window could be opened, if necessary.

In order to ensure that all residences have access to the healthful aspects of natural ventilation, state or local building codes commonly regulate the minimum size of the ventilation opening in a window and the egress opening. Typically, codes require that about 5 percent of the floor area of a "living area," such as a bedroom or living room, be provided in ventilation area. These regulated areas should be carefully checked before sizing or replacing a window.

Guidelines for Providing Fresh Air

• Place operable windows in all rooms to give occupants opportunity for fresh air.
• Provide cross-ventilation by placing window openings on opposite walls in line with the prevailing winds.
• Use casement windows to direct and control ventilation.
• Use operable skylights or roof windows to enhance ventilation.
• Use landscape elements to direct breezes.