At in-town speeds, the AC will eat gas. On the highway there's potential for the open windows to creat an adverse aerodynamic condition that would be worse.
BUT, my car has a MPG meter on its nag screen, and even at 70 on the crosstown expressway I'm better off with the AC off and a window open.
BUT, my car has a MPG meter on its nag screen, and even at 70 on the crosstown expressway I'm better off with the AC off and a window open.