Why Does Attic Need Ventilation

First it allows cool fresh air to enter into the attic.
Why does attic need ventilation. Effective ventilation provides year round benefits creating a cooler attic in the summer and a drier attic in the winter. Attic ventilation fans help cool air your attic by pushing out the stifling hot air from inside the attic and bringing in cool air from outside. For similar reasons your attic needs to breathe also. Attic ventilation is an intake and exhaust system that creates airflow designed to decrease the difference in temperature between the outdoor air and the air inside the attic.
While we have an active process most homes have a passive venting system which requires a balance between the intakes and outlets. Second it allows hot moist air to escape. Ventilation only works when air flows. A balanced attic ventilation system that consists of intake at the eaves soffits or fascias of the roof and exhaust at or near your roof ridge serves two important functions.
That said air resistance and interference such as vent grates reduces the area of true ventilation. Roof ventilation works by allowing air to flow through the attic which prevents it from becoming overheated and causing moisture. Intake vents located at the lowest part of the roof under the eaves allow cool. Attic ventilation works on the principle that heated air naturally rises primarily utilizing two types of vents.
There are two primary methods to create air flow within an attic. In cold climates the primary purpose of attic or roof ventilation is to maintain a cold roof temperature to control ice dams created by melting snow and to vent moisture that moves from the conditioned space to the attic ventilation acts to bypass the vapour barrier created by most roof membranes. This prevents hot air from seeping into your home and driving up the temperature in the living space which reduces the load on your air conditioner. Proper ventilation in your attic helps address excess heat and moisture that can otherwise wreak havoc on your home.
In other words the entire vent opening doesn t count as vented space. We need to breathe to get fresh air in and out of our bodies. Requires a power source. Heat and moisture buildup in an attic cause predictable but different problems in hot and cold climates.
Whenever possible natural roof ventilation is used. Why adequate roof ventilation is important. In the winter allowing a natural flow of outdoor air to ventilate the attic helps keep it cold which reduces the potential for ice damming snow that melts off a roof from an attic that is too warm and then re freezes at the gutters causing an ice dam that can damage the roof.