In cold weather, warm air generated by laundry, showers, dish washing and cooking can linger in the house and cause moisture build-up. In the summer, heat build-up encourages premature aging and cracking of wood and roofing materials.
Unwanted heat can also transfer back down into living areas, reducing energy efficiency.
The only way to combat these problems is with a balanced ventilation system. In a balanced system, wind blowing over the ridge creates a negative pressure that draws the warmer air out of the attic. Replacement air enters through the undereave or soffit vents, bathes the underside of the roof, and exits at the ridge cap through ridge vents, roof vents or gable vents. Even with no wind, the natural convection action of rising warm air maintains a continuous airflow along the underside of the roof. It's a system that works year 'round with no moving parts or energy consumption.