i'm always so surprised when people let their fabric get exposed to the sun - we all know how much money goes into our stash - why on earth would you do that.
i have a walk in closet that is floor to ceiling shelves and i keep everything in the closet.
even my design wall is behind curtains so that my WIP doesn't get exposed to the sun. i open the curtains when i'm working and close them when i'm done for the day.