Attic insulation diagram
11 July 2012

Attic Ventilation for Your Home

Attic insulation diagram Attic insulation diagram

Why Do I Need to Have Attic Ventilation?

Proper attic ventilation is needed to keep the attic space cold in the winter and to have the ability to remove the very hot air that accumulates in the summer. If the attic isn’t allowed to become cold in the winter ice damming may form causing damage to the roof. During the summer months the hot air needs to escape. This will also protect your roof and remove the hot humid air that can collect in the attic.

How Much Attic Ventilation Do I Need?

Use the 1/300 rule. This means that for every 300 sq/ft of attic space you will need 1 sq/ft of ventilation. Convert the total needed to square inches and use half of that amount for the soffit and the other half for the ridge. Vents are labeled in square inches. Example 2,000 sq/ft attic- 2,000/300= 6.67. Convert to square inches 6.67 x 144= 960 sq/inches. 960 x 50%= 480 sq/inches for the soffit and 480 sq/inches for the ridge.


Leave a Reply