On of the most common questions we are asked is, “Does the notch for the tilt bar go to the top or the bottom of interior shutters?”
The notch for the tilt bar indicates the top of movable louver interior shutters. The tilt bar notch allows for the louvers to close fully. You want the louvers to close to the top so it fully blocks direct downward streaming sunlight. If the louvers closed to the down position, there would be a sliver of space for light to enter.