Not everyone has a dryer. In fact, most rentals tend to come with a washer only (annoying, IKR), but that doesn't mean you can't dry your comforter. In fact, drying your washing naturally is less damaging to your duvet and better on your energy bills and the environment.
To dry your comforter without a dryer, set up a clothesline or drying rack in a warm dry place, inside or out. Hot weather and wind will help your duvet dry quicker, and direct sunlight will brighten white fabric and fade any stains.