I have my fabric in cupboards with doors on and they still fade a little so if you were to put some thing dark over the windows or board them up maybe it will prevent fading. It doesn't matter what kind of light it is, they will fade if your lights are on all the time or natural light too.You will have to re-fold your fabrics every so often to help them from fading in the one place. It is finally your decision so weigh up the pros and cons then you decide which is the best for you. Unfortunately dust gets in no matter which way you go.