What is natural ventilation?

Natural ventilation can be anything from an open window to large complex systems with double skin facades, ducts and dampers, chimneys and computer control for multiple parameters.

Natural ventilation means that there is no energy used to move air, instead it is the "natural" drivers moving air.



The driving forces of natural ventilation can be

  • Pressure difference. There will usually be a difference in the air pressure on the two opposite sides of a building. This is particular used by having cross ventilation, where you have openings on both sides (e.g. windows). Cross ventilation is the most simple (and effective) form of natural ventilation.
  • Thermal buoyancy (stack effect) - where warm air rises and cold air falls. This could be exploited by double skin facades, 3G windows, chimneys and atriums.
  • Wind - either directly or by means of "wind cowls," which is a kind of wind-powered ventilators.



Reduced energy consumption

Natural ventilation regulates the indoor climate by a controlled air flow through the windows. Compared to mechanical ventilation natural ventilation uses only a small amount of energy when the windows open and close. A head to head comparison shows that natural ventilation has a 40% lower CO2 emission than a system with mechanical ventilation.