I've seen the turbine turn when there was NO wind moving the leaves
outside though it was warm inside the garage. Turbines DO NOT NEED A
WIND TO TURN. Our garage didn't have any vents as built. Find the
definition of "convection" which is what warmer air rise.

On Tue, 24 May 2005 17:44:18 GMT, "Joseph Meehan"
wrote:

nospambob wrote:
The 20° drop IS appreciated almost daily. The outrush of hot air when
the roofer cut the hole was impressive!

Which is a really good indication that you did not have enough high
vents to start with. Likely any added vent, including passive (ridge or any
non-powered roof vent) would have done very well. The turbine vents can add
some additional venting when there is a wind.