Not at all! When I started building Xronos Clock my primary concern was that brightness of LED display will bother me at night and I won’t be able to fall asleep. Indeed naked LED matrix is pretty bright on it’s own, even at lowest setting. However Xronos Clock uses thick (6mm) and very dark acrylic in the front that dims light sufficiently. Set to Auto Brightness or Night Mode it’s not brighter than any off the shelf alarm clock I previously had.  Additionally you can select font that uses less LEDs making clock emit even less light.