Controllable ventilation is found throughout the home,kitchens, bathrooms, utility rooms, living rooms and bedrooms all have ventilation that is controllable.
While kitchens, bathrooms and utility rooms have forced ventilation, living room and bedrooms have passive vents.
Why are they termed controllable? Because we decide whether to use them or not and if we do decide to use them we have the choice as to the length of time they are used.
The need to ventilate our homes is well known and the different types of ventilation have differing purposes. Forced or mechanical ventilation is used to control moisture within the air, when cooking, showering, cleaning cloths, etc. These forced ventilation systems, provided by extract fans, within each room are designed to operate for a given purpose.
Kitchen fans attached to the cooker hood will extract the moisture from cooking at source and travel along ventilation ducts to the outside, these fans operate at a maximum discharge rate of 30 litres per second and if the kitchen fan is remote to the cooker then an extraction rate of 60 litres per second is used.
Likewise, bathroom fans are set at high level and extract the moist air produced while showering. This fan is designed to extract at 30 litres per second. Utility room fans are designed to extract at 30 litres per second. You may have other extract fans within the home such as in toilets that have no windows, extract fans in these locations will extract at 6 litres per second.
Passive vents are used to control temperature and air quality within the home. Trickle vents in the windows allow a small quantity of air into and out of individual rooms within the home. When a lot of ventilation is required in these rooms, opening the window usually is enough, if it is not sufficient then opening windows in other rooms and leaving the doors between them open will allow an intake of air and an extraction point.