If you tend to sleep cooler and need added warmth, a heavyweight comforter or duvet insert is the way to go. However, just because a comforter has a heavier fill, doesn’t mean you have to sacrifice breathability. Look for a comforter that has a natural cotton shell rather than a synthetic one. Go for one with fill material that’s warm yet breathable, light, and moisture-wicking, like down alternative and lyocell.