Soffit venting is a type of venting method that allows air to flow into your attic from under your roof's eaves. One benefit of soffit vents is to minimize moisture. An excess of moisture that can build up inside the attic during rainy or humid days needs to be properly ventilated so items stored up there don't get damaged or create mildew problems. Another problem resulting from poor venting is from the heat build-up from the sun shining on the roof during the day in the winter months melting the snow sitting on it and creating amounts of water that will later freeze up during the evening and at night, creating dams that will cause water to leak through causing considerable damage to your home. To minimize or eliminate such problems, you need soffit vents in conjunction with ridge vents or any other type of exhaust vents.
Proper attic ventilation protects a home and its occupants from the effects of temperature swings. During the summer, hot air inside the attic causes the temperature inside the home to rise as well. Soffit venting mitigates this temperature build-up, reducing the need for air conditioning as well as protecting the home from the damages caused by extreme heat.
The purpose of the ventilation is first of all to remove the warm air from the attic. This can be naturally addressed by using a simple law of physics where heat or warm air naturally rises above colder air. So by creating a "path" for cooler air to infiltrate the attic at the floor level, this incoming air will force the warmer air to exit through the higher ridge vents or other types of roof vents installed higher on the roof gable. The soffit venting will keep the roof cold during the winter months, preventing snow from melting on your roof, flowing down into your gutters, and refreezing as an ice dam but will also reduce mold-causing moisture inside the attic during the summer.
Soffit vents are intake vents installed in the eaves to draw in cool air from the outside and allow warm air to escape out of the exhaust vents. Soffit vents are never installed without other types of vents installed at a higher location to draw air and moisture out of the attic.