For many precious collectibles, the darker and colder a room is, the better. Of course we can't live in the dark -- but keep your stuff out of the window, out of direct sunlight and away from light sources as much as possible.
Personal experience:
We displayed a patriotic Christmas tree in the living room window, using a few inexpensive (thankfully) glass pieces facing the outside window. When the holidays were over, the balls were not red, white and dark blue, more like pink, white and baby blue.
From Saving Stuff: Double the life span of your stuff by lowering your temperature 18 degrees. If you can't handle that, compromise at around 70 degrees.
