The purpose of attic ventilation is to remove hot air from the area between the roof of the home and the living space. Ventilation can be either powered or passive.
Passive Ventilation comprises vents at the top or at the ridge of the roof, supplemented with vents at the underside of overhanging eaves. The convection current causes the hot air to rise at the top and exit the vents at the ridge and fresh air enters from the soffit vents.
Powered vents utilize fans that are powered by electricity to propel the air out of the attic and fresh air enters the attic through passive vents.
Both methods have their own advantages and disadvantages.
Powered vents make noise as they have fans.
However, the majority of the times the volume of noise that reaches indoors is not much, as it is reduced due to the house’s building materials and insulation.
Powered vents are generally more expensive than passive vents. As passive vents are basically just covers or grills that have no moving parts, whereas powered vents comprise a fan or a blower and an electric motor, they are more costly.
It takes more times to install the fans than installing a passive vent. It is also important that there are separate electrical lines in the attic insulation to install the powered vents. Not having any can further increase the installation costs
A proper ventilation ensures that the energy costs are reduced, as less electrical power would be used in air-conditioning and while the actual cost of the operation of powered vents depends on the runtime, they only use about 300 watts, and can ultimately help you save money. Powered vents that run from solar-energy are also available.
As powered vents run on electricity and are mechanical contraptions, the biggest downside is that they can fail. The repair or replacement of the powered vents can lead to additional costs.