Homeowners have recognized the need of some type of attic ventilation for generations, but it wasn’t required in building codes until 1948. Attic ventilation includes gable vents, ridge vents, soffit vents, and in many instances a fan to move the air through the gable vents.
The gable is the triangular portion between the intersecting roof profiles. Gables vents are most often used in sharply pitched roofs characteristic of Gothic and classical Greek styles of architecture and are often found on farm houses.
Attic ventilation is important to:
reduce the chance of moisture build up in attics or condensation on the underside of roof sheathing
extend the life of shingles
lower cooling costs in the summer by eliminating heat buildup in the attic