Roof Ventilation Definitions

Ridge soffit vents importance of balanced roof ventilation.

Roof ventilation definitions.

The goal of hvac design is to balance indoor environmental comfort with other factors such as installation cost ease of maintenance and energy efficiency. Cool air in hot air out attic ventilation works on the principle that heated air naturally rises primarily utilizing two types of vents. Some ridge vents feature an external baffle which helps to steadily vent air out of an attic and protect against weather infiltration. Hvac heating ventilation and air conditioning is a major subdiscipline of mechanical engineering.

About 90 percent of homes in the us have unreasonably high levels of moisture. Intake vents located at the lowest part of the roof under. In a hot climate roof vents expel hot air from the roof or attic while relieving the load on the air conditioning system. Ventilation problems can be seen in a variety of ways such as blistering and peeling paint on the gable end exteriors because of excessive heat and moisture.

Roof ventilation in a cold climate vents moisture and ensures a cold roof temperature to avoid ice dams. Here are some of the myths and the facts you need to know about attic ventilation. In essence all ventilation is about circulating air to keep it fresh and to reduce moisture levels. This configuration also tends to evenly wash the entire underside of the roof surface with ventilation air.

Understanding whether your home could benefit from some form of attic ventilation might just be if not a life saver a roof saver. 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. To achieve full ventilation of the attic there must be an air inlet at the base of the roof through perforations in the eaves soffit. For both attics and cathedral ceilings roof ventilation works best when it is balanced between high and low to take advantage of natural convection figure 2 55 at left.

The building codes and building science for natural roof ventilation however only appeared in the 1940s. In a properly designed and installed attic ventilation system that means the air will flow from the intake vents to the exhaust vents flushing out the warm moist air along the entire underside of the roof deck. Most often made of perforated aluminium this piece closes off the underside of the eaves.