The typical old Florida house might whistle a bit but I doubt you would really generate any real vacuum. I have 2 big "whole house" fans that exhaust into the attic. Occasionally my kid would turn them on without opening any windows. You would think it would make your ears pop but it just demonstrated how leaky crank out "awning" windows really are. I can see it on my barometer tho. Sometimes the storm warning will go off from the rapid pressure drop.
