When the wind direction is perpendicular to the ridge, it strikes the external baffle and jumps over the ridge. That movement creates a Bernoulli Effect, causing low pressure to develop on both sides of the vent. When that happens, air from the attic is “lifted” out, in much the same way low pressure created above an airplane wing gives “lift” to the plane. The same thing happens when the wind direction is parallel to the ridge. It moves across the louvers, creating low pressure areas on the louvers on both sides of the ridge vent. In addition, when there is little wind force, ridge vents take full advantage of the thermal effect to maintain air circulation across the underside of the roof sheathing. Warm air rises and exhausts through the vent which allows a continuous flow of cooler air to enter through the intake vents. Only ridge vents use this thermal effect efficiently and effectively because only ridge vents provide continuous and uniform air movements along the length of a roof. |