Things You'll Need
Cotton bag or large cotton pillowcase
A duvet is a fluffy comforter that is traditionally filled with down feathers. Duvets provide a lot of insulation, and are commonly used for bedding during the winter. Because duvets are so warm, many people choose to store them for the summer and switch to a lighter comforter or quilt. Duvets are easy to store because they are mostly air, so they can be compressed to very small sizes. To ensure your duvet is stored without any damage, pack it carefully and choose an appropriate storage location.
Find a cotton bag or large cotton pillowcase to store your duvet. Down feathers need some airflow during storage, so they should not be stored in plastic (if your duvet is made from synthetic materials a plastic bag is acceptable). Ideally your bag should have a drawstring or zipper to close the top, but this is not necessary.
Fold your duvet, pressing it flat to reduce its volume. Place the folded duvet in your bag and pull the drawstring or fold the top of the bag closed.
Place your duvet in a dry location. It is incredibly important that your duvet stay dry during storage, because mildew can easily ruin a down comforter. If your attic or closet is humid, choose a different room.
Remove your duvet from its bag when you are ready to use it. Hold the top corners of the duvet and shake it out to fluff the down feathers before putting it back on your bed.
Duvets should only be washed if absolutely necessary, and even then most home washers cannot properly handle a down comforter. Instead of washing your duvet, use a duvet cover (a sheet bag that slips over your duvet) and wash the cover like you would wash your other bedding.