Ridge vents are great, I had them put in when my roof was replaced due
to hail damage last year, but you need both low and high vents to create an
air flow. You want the hot air to go out the top (ridge vents or gable
vents) while cool air comes in the soffit vents. There can even be a problem
when the mix of vents creates a short circuit so part of the area does not
get ventilation.


Well, it works BETTER with a ridge vent and soffit vents, but it's
not actually necessary. If you have ridge vents and gable-end
vents, then hot air will go out the ridge, and possibly out the
down-wind gable, and replacement cold air will come in the
up-wind gable and possibly the down wind gable. As long as
there's a way for cooler outside air to get into the attic, it
will pool on the floor, forcing the other heated air out.

Likewise with the turbine vents. They will not pull air
out of your living space if there is anywhere easier to
get it from.