At what outside temp do you disable your solar sunroof fan?

There is no need to disable it. It won't run if the temp. drops.

 

It works when the temp is 78 or above.

 

Even though it won't run the fan, it will still cycle the system when the temp is low. So I shut it off during the winter so that I don't hear the "flatulence" noise when the roof sees the sun.