How does outdoor air enter a house?

Outdoor air enters and leaves a house by: infiltration, natural ventilation, and mechanical ventilation. In a process known as infiltration, outdoor air flows into the house through openings, joints, and cracks in walls, floors, and ceilings, and around windows and doors. In natural ventilation, air moves through opened windows and doors. Air movement associated with infiltration and natural ventilation is caused by air temperature differences between indoors and outdoors and by wind. Finally, there are a number of mechanical ventilation devices, from outdoor-vented fans that intermittently remove air from a single room, such as bathrooms and kitchen, to air handling systems that use fans and duct work to continuously remove indoor air and distribute filtered and conditioned outdoor air to strategic points throughout the house. The rate at which outdoor air replaces indoor air is described as the air exchange rate. When there is little infiltration, natural ventilation, or mechanical ...  more

Outdoor air enters and leaves a house by infiltration, natural ventilation and mechanical ventilation. Infiltration means that outdoor air comes into the house through openings around windows and doors, cracks and joints. Natural ventilation occurs when air comes through open windows and doors. Mechanical ventilation includes devices such as outdoor-vented fans that remove air from a single room, and systems that use fans and ductwork to continuously remove indoor air and distribute filtered and conditioned outdoor air throughout the house. Air exchange rate is the rate at which outdoor air replaces indoor air. When the air exchange rate is low, pollutant levels increase. Health Effects of Indoor Air Pollutants Health effects from indoor air pollutants may occur immediately after exposure or even years later. Immediate effects include irritation of the eyes, nose and throat, headaches, dizziness and fatigue. These are usually short-term and treatable by removing the person from ...  more

Outdoor air can enter and leave a house by infiltration, natural ventilation, and mechanical ventilation. In a process known as infiltration, outdoor air flows into the house through openings, joints, and cracks in walls, floors, and ceilings, and around windows and doors. In natural ventilation, air moves through opened windows and doors. Air movement associated with infiltration and natural ventilation is caused by air temperature differences between indoors and outdoors and by wind. Finally, there are a number of mechanical ventilation devices, from outdoor-vented fans that intermittently remove air from a single room, such as bathrooms and kitchen, to air handling systems that use fans and duct work to continuously remove indoor air and distribute filtered and conditioned outdoor air to strategic points throughout the house. The rate at which outdoor air replaces indoor air is described as the air exchange rate. When there is little infiltration, natural ventilation, or ...  more

Outdoor air enters and leaves a house by: Infiltration, natural ventilation and mechanical ventilation. Infiltration is the process where outdoor air flows into a house through openings, joints, and cracks in walls, floors, and ceilings and around windows and doors. In natural ventilation, air moves through open windows and doors. Air movement associated with infiltration and natural ventilation is caused by air temperature differences between indoors and outdoors and by wind. There are a number of mechanical ventilation devices, from outdoor-vented fans that intermittently remove air from a single room such as bathrooms and kitchens, to air handling systems that use fans and duct work to continuously remove indoor air and distribute filtered outdoor air to strategic points throughout the house. The rate at which outdoor air replaces indoor air is described as the air exchange rate. When there is little infiltration, natural ventilation, or mechanical ventilation, the air exchange ...  more