Passive Ventilation

From Swikipedia

Introduction

Passive ventilation relies typically on using both convective air flows that result from the tendency of warm air to rise and cool air to sink and taking advantage of prevailing winds. Many passive ventilation systems rely on the building users to control window and vents as indicated by site conditions and conditions within the building.

Brief Description

Ventilation is needed to bring fresh air into a home and to remove stale, moist or polluted air. It may also be needed for cooling.

Passive ventilation can be:

• controllable air movement through openings such as windows, doors from wind pressures and/or indoor-outdoor temperature differences

• uncontrollable air flow through unintentional openings in the building envelope (infiltration) resulting from wind and temperature generated pressure differences across the building envelope

Passive ventilation is the least expensive and most environmentally friendly way to ventilate a home. However, in some situations passive ventilation on its own will not be enough:

• wet areas such as bathrooms will need extract systems to remove moist air

• airtight homes may need a supply system to bring in heated, drier outside air

References:

http://www.greenbuildingcookbook.info/Glossary.html

http://www.level.org.nz/passive-design/controlling-temperature/passive-ventilation/