Standard home washers hold about 12 pounds. A queen comforter weighs 7 pounds dry — and 15+ pounds wet. The math doesn't work, and your machine knows it.
What goes wrong
Comforters absorb so much water they can't tumble freely. The fill bunches to one side, the wash isn't thorough, the rinse isn't complete, and your washer rocks itself off-balance trying to spin a brick of wet down.
The smarter move
Industrial-capacity washers (we run 40, 60, and 80 lb machines) have the drum size to actually tumble a comforter properly, and the spin force to wring it dry. The whole job takes 90 minutes instead of three home cycles that still leave it damp in the middle.
Flat-rate comforter wash starts at $22. Drop it off in the morning, pick it up clean and fluffy by close.