House ventilation
House ventilation is an important part of the health of any home. Poor ventilation can lead to mould, building damage and bad health which is often caused by a build up of excessive moisture. Windows are the first defence against this by opening them you will be able to increase the air quality with in the house. In most cases, the air quality outside is better than the air quality inside a house unless the house is subject to a high pollution environment. The main types of house ventilation are passive and mechanical and both are use in most modern houses.
Passive Ventilation
Passive ventilation depends on outside wind pressure and temperature to move the air through the house structure.
Mains powered extraction fan
Passive ventilation areas
- under floor ventilation – this applies to timber flooring and moving moist air out from under the house.
- Living area ventilation – This is the ventilation required by people – bathrooms, kitchens – ventilation through windows and doors.
- Attic or roof cavity ventiltion – removes hot and moist air between the ceiling and the roofing.
All of these areas are important and must be applied to all homes to control the build up of heat and moisture. Under floor ventilation does not apply to concrete slab floor homes, only houses with a raised floor or a floor that is not in contact with the ground. Passive under floor ventilation uses the natural wind pressure to force moist air out and drier air in. The air is forced out through the air vents and also as the air in the roof cavity starts to get hot and rise it is drawn out of the roof vents and drawn in through the under floor vents. In concrete slab houses the same effect takes place, only the air is drawn in through vents in the wall and not from under the floor.
Mechanical Ventilation
Mechanical ventilation is also found in most homes in the form of exhaust fans in the kitchen and bathroom areas to remove extra moisture. These are very common and however many of them just exhaust the air into the roof cavity and not outside. The best way for the health of the building is to always exhaust high moisture air outside. This can be achieved by using ducting and one way vents to get rid of the unwanted moisture. Also in hot areas mechanical roof ventilators also help to actively remove hot air in the roof cavity and draw in cooler air. This helps reduce the temperature on the inside of the home and can also have an lowering effect on air conditioning costs.
solar powered extraction fan
Common Types of Mechanical Ventilation
- Kitchen exhaust fan – range hood exhaust fans.
- Bathroom exhaust fans.
- Wind powered roof fan vents.
- Electrical (mains powered) roof fans
- Solar powered roof fans.
The solar and mains powered extraction fans are mainly there to remove hot air and can be wired to a thermostat to switch on and off at set temperatures.
Special Use Extraction Fans
Wind powered extraction fan
These fans can be either mains powered or solar powered and are installed in houses without proper ventilation or houses that have excessive ground moisture. They actively remove high moisture air out of the building and replace it with dryer air. They can be also set to come on when the moisture level is too high to remove the air and stop as the moisture levels fall. This keeps the building healthy and in turn the people living within the building healthy as well. These types of fan assist with combating excess ground moisture levels, rising damp, and condensation levels.
Check out a House Ventilation pages for more information.
