According to the rule of thumb, how much net-vent opening is recommended for every square foot of insulated ceiling?

The recommended net-vent opening is 1 square foot for every 150 square feet of insulated ceiling. This guideline helps ensure adequate ventilation in the attic, which is crucial for maintaining optimal temperature and moisture levels. Proper ventilation can prevent issues such as condensation, mold growth, and damage to roofing materials.

The ratio of 1:150 balances the intake of cooler, outside air with the escape of warm, moist air that naturally rises to the attic. This ventilation strategy is particularly important in the summer months to help keep the attic space cool and reduce the load on air conditioning systems, as well as in winter to prevent excess moisture buildup that can lead to structural problems. Thus, understanding and applying this ventilation guideline is essential for effective attic inspection and ensuring the longevity of the home.