Vents evenly spaced underneath the roof provide intake. To calculate an example of exhaust and intake, use 25 feet of roof ridge vent. Multiply it by 18 square inches (the net-free air per foot of ridge). This gives you 450 square inches of total exhaust. Since exhaust and intake must be equal, 450 square inches of total intake is required as well. Roof Ridge Vents Are Not Ideal for Every Home. Depending on the age and design of your home, roof ridge vents may not be the most effective ventilation system. Older homes, for example, still need older ventilation systems that work with how the home was designed. Ridge vents will only work as they should if the rest of the home is designed to. Jan 06, 2021 · A ridge vent is an air exhaust vent installed on the peak of a roof. When installing this vent, an air slot is first cut in the roof deck at the roof's peak. This air slot is then covered by the ridge vent itself. They help to provide continuous, uniform exhaust ventilation at the highest portion of the attic and are designed to help resist .... Ridge vents ensure adequate air flow in your loft space, which helps to prevent moisture and condensation build-up. Choice of styles. Buy now. Order Helpline: 01295 565565 | ... Roof ridge vents are installed at the apex of a roof to allow warm air to easily escape the loft space. When used alongside tile or eave ventilation, a ridge vent will.