Installing roof vents in Atlanta is essential. Moving hot air from the attic out of the roof vent reduces the cooling load on your home, thus reducing your energy bills. Well-ventilated roofs reduce attic temperature by up to 10 degrees Fahrenheit.
In most homes, code recommendation is a 1:300 ratio of vent area to insulated ceiling area; however, you should consult building codes or a roofing professional for exact ratios in your city or county.
If you do choose to install roof ventilation in the attic, you need to create a barrier between your air-conditioned space and ventilated attic space. An air barrier must be installed at the ceiling line.
Some builders are building vent-free. With wind-driven rains caused by the aftermath of hurricanes and tropical storms, roof vents can be somewhat problematic in Atlanta.
If you have a finished attic or an attic that holds ductwork and thus needs air conditioning, you'll want to consider venting your roof deck instead of the attic. If you have a complicated roof structure (dormers, hips, etc.), this approach is more difficult. In this case, you may want to consult a roofing professional or consider an unvented solution.
Note that if you choose an unvented approach, your shingles or other roofing material will be operating at a higher temperature. In the case of asphalt shingles, this can reduce their life by up to 10 percent. Particularly in the humid Atlanta climate, you'll also want to pay careful attention to protecting the roof from condensation from your air conditioning. The air barrier needs to be properly insulated to allow an unvented roof.