Common home ventilation options include natural ventilation, exhaust-only mechanical ventilation, supply-only mechanical ventilation, balanced ventilation and balanced ventilation with heat recovery. Most homes use no ventilation, which prevents fresh air from circulating throughout the home.
Natural ventilation is used in a home in which specific design features are incorporated that bring in fresh, clean air and get rid of musty air. Design implements may include a solar chimney that allows inside air to be heated by the sun. This heated air rises and exits through vents located near the top of the home. As the air exits and the air pressure in the home is reduced, fresh air is drawn in through strategically placed inlet ports.
Other ventilation options include exhaust-only ventilation, which uses small exhaust fans placed throughout a house to expel stale air as well as moisture. Air is drawn in through cracks, leakage sites, or man-made inlets throughout the home. In a supply-only ventilation system, fresh air is pushed into the home using a fan. The air may be dispersed through ducts or released from a central location. Old air is forced out through cracks and leakage sites.
Another ventilation option is a balanced ventilation system in which separate exhaust fans are used to bring in and expel air throughout the home. These exhaust fans may use an air-to-air heat exchanger so that air brought in from the outside may be preconditioned and temperature-appropriate. This ventilation system is preferable to exhaust-only and supply-only ventilation systems, as both air expulsion and air intake are controllable.