Ventilation has been defined as entry of outdoor air in the indoors using some means that may be natural or mechanical. Mechanical ventilation means that some sort of appliance or machine is used for ventilating buildings. Among mechanical means are exhaust fans and inlet fans that pull in air for reasons that stale air has to be removed. Ventilation is built into many building designs with spaces in louvers, doors and windows where air can be enter buildings.
Ventilation is something that is essential for survival of humans. Ventilation is ensured through the use of naturally powered fans as well. There are pressure differences between indoors and outdoors thus enabling the fans into operation. There is not just stale air that has to be removed there are dust particles and sometimes even smoke that has to be removed from homes.
Smoke comes out from kitchens. Outdoor air when fresh and unpolluted causes people to breathe in fresh air. Outdoor air when that enters the buildings causes temperature to rise inside homes or fall as well depending upon temperature outdoors. Ventilation makes buildings last longer as well. Humidity being driven away from indoors causes the buildings to last long as walls and ceilings do not absorb moisture in absence of moisture indoors.
Buildings that are designed to allow air inside are called as well ventilated. These are also called as green buildings. In colder regions of world there are buildings designed to allow maximum sunlight in and are insulating in nature. Ventilation is essential in colder regions in summers as in summers there is pleasant air outdoors that has to be used indoors for breathing.
In warmer regions of world there is ventilation needed in all seasons. In summers ventilation causes air from outdoors to flow indoors driving away moisture and humidity which makes people inside perspire in absence of air conditioning. Air conditioning in itself cannot make buildings ventilated. In addition to air conditioning, there is ventilation that is essential from multiple viewpoints.
In modern office buildings that are being built in Australia, ventilation systems bring in fresh air from outdoors filter and cool that air while driving out stale and humid air indoors. Recently there has been a concept of passive ventilation; that is designing buildings in a way that makes them ventilated without using active power. Ventilation vents Australia wide being made is a testimony to that.
