No, however, your results will be better if you include at least 6 wool dryer balls in the dryer with the down comforter. Optionally, if you don't have wool dryer balls, you can use clean tennis balls, which will give similar results. The way these balls work is that as the comforter tumbles, the balls bounce around, keeping the folds of the comforter open, allowing the warm air to circulate more freely. That allows the feathers and down to open up within the comforter, releasing water and allowing the whole thing to become dry and super fluffy. If you do not use wool dryer balls or tennis balls, it will take a bit longer to dry. The comforter, while still perfectly useful and clean, may take a while to re-fluff.