How can I decide between passive and active attic venting?

Question

How do you decide which one to install? This is for a 2200 square feet, one-story, 40-year old home in the hot and humid Southeast Texas. During our last roof renovation, many years ago, the contractor replaced the electrical fan with a turbine vent. Now the roof has two turbine vents. I am concerned about inadequate attic ventilation and condensation buildup on the drywall ceiling.

We have replaced the wooden soffit with vented Hardie-board soffit (has many holes in it). The attic has the original fiberglass flooring insulation. Under the shingles there is only a plyboard.

Answer 1

There's nothing to decide unless you enjoy paying for electrical power you don't need. If you need more ventilation, add more in the form of additional turbines or full-length ridge venting.

I don't see the relationship between attic temperature and ceiling moisture, though. Condensation typically comes from moisture inside the home, and it condenses on cool surfaces. You're dealing with neither of those. If you have enough heat migrating through the attic insulation that its surface is cool and condensing, you have an insulation problem, not a venting problem. Or both.