When quilts are not in use they need to be stored to prevent or at least limit damage. Quilt storage is best done by being layed flat, unfolded and ideally not stacked. Unfortunately most people don't have the luxury of living where that can be done.
The ideal place is where you and I can be comfortable. A place that is not too hot, too cold, too damp or too humid. That removes the attic and the basement. Also places with too high a humidty level can cause mildew to grow on your quilts.
The best place is within the living areas of your home that are not near the kitchen, bathrooms or outside walls. The area must also allow for air circulation. So storing them in plastic is ill advised. Wrapping your quilts in clean unbleached muslin or cotton sheeting is best, but remember to wash this each year.
Another consideration is the shelving they are going to rest on as unsealed wood can color your quilt over time. A coat of polyurethane to seal the wood, would be helpful.
Photo Courtesy of Rowena of the Rants
If you're like me you began storing your unused quilts by folding them so the topside of the quilt was innermost. This I found out can put strain on the fabric and threads at the fold. If this is your method of storage then remember to change the position of the folds from time to time to reduce permanent creasing or wear marks from developing.
More recently I discovered rolled storage. Some say this is better than folding as it exerts less stress on the fabric. Roll your quilt loosely onto a large tube avoiding wrinkles. Wrap it in muslin or cotton sheeting.
Which ever way you choose to store your quilts remember to get them out and lying flat for a few hours, at least once a year. Give them a gentle vacuum to remove dust. This will also help you check for any unwanted visitors that have made a home in your quilts.
Here is a new idea on the market. It is called the quilt storage system 'Hang'n It'. Watch the short movie to see how versatile this is. It really does hold and display a lot of quilts.
My mother-in-law still uses mothballs when she stores her beautiful hand knitted winter clothing to keep them pest free. If you feel there maybe a pest problem where you live then place a few mothballs in a woven bag and suspend this from the top of the cupboard for a couple of months.
Quilt storage for old or antique quilts requires a specific method to help protect the quilt from further damage, thus preserving it for future generations. You will need to use acid-free tissue paper. Following is a video with Bobbie Aug demonstating this method.