How to wash a sleeping bag (down or synthetic) without ruining the loft

Step by step: how to wash a sleeping bag

Safety first. Use low heat and check the bag every 20 to 30 minutes in the dryer. High heat can melt lightweight shell fabric, and a shell touching a hot dryer drum can be damaged for good.

1. 1

   Read the care label and check the fill

   Find the care label and see whether the bag is down or synthetic and what water and dryer temperature it allows. Most sleeping bags are machine washable, but the label wins. Do not dry clean it; both Big Agnes and NEMO advise against it.

2. 2

   Spot clean small marks instead of washing

   For a few dirty spots, pull the shell fabric away from the insulation, then scrub just the fabric with a soft brush and a paste of non-detergent soap and a little water. Wipe with a damp cloth and air dry. This saves a full wash, which is harder on the bag.

3. 3

   Zip it up and turn it inside out

   Close every zipper, fasten any hook-and-loop tabs so they do not snag, and turn the bag inside out. Empty the stuff sack pocket and remove any liner.

4. 4

   Use a large front-loading washer

   Load the bag alone into a front-loader with no center agitator. An agitator can tear baffles and shift the fill. Double-wide and winter bags usually need an extra-large laundromat machine so they can rinse clean.

5. 5

   Add a down or gear wash, not regular detergent

   Use the dose on the bottle of a down wash for down bags or a technical wash for synthetic bags. If you must use regular detergent, use a very small amount of liquid, never powder. Add no fabric softener, bleach, oxygen booster or wash-in waterproofer.

6. 6

   Wash on gentle with an extra rinse

   Run a gentle or delicate cycle at the water temperature the label allows (cold is the safe default) and add an extra rinse. Leftover soap is the main reason down clumps after a wash.

7. 7

   Lift it out carefully

   A wet sleeping bag is heavy and the wet baffles can tear if you pull it by one end. Scoop it out in a bundle with both arms and carry it to the dryer supported from underneath.

8. 8

   Tumble dry low with tennis balls

   Dry it in a large front-load dryer on low heat (or the warmest setting the label allows) with 2 or 3 clean tennis balls. Take it out every 20 to 30 minutes to fluff it and break up clumps by hand. Expect 2 to 4 hours and several cycles.

9. 9

   Check that it is completely dry

   Feel each baffle for small, hard clumps; clumps mean the fill is still wet. Keep drying until the bag is evenly lofted. Then hang it or lay it out for several more hours, or a day, before storing so no moisture is left to grow mildew.

How to wash a down sleeping bag vs a synthetic one

Both go in a front-loader on gentle, but down needs a down-specific wash and a long, patient dry, while synthetic dries faster on low heat. The main difference is the soap and the drying.

Big Agnes recommends Nikwax Down Wash for down and Nikwax Tech Wash for synthetic fill, says to use a very small amount of liquid detergent if you have nothing else, and warns that too much soap makes down clump. It also says to skip any wash-in down waterproofer, because its down is already treated and the additive causes clumping. Nikwax notes that regular detergents can damage the natural properties of down.

Why the washer and dryer matter so much

Use a big front-loader because a top-loader’s agitator can rip the internal baffles, and use low heat because sleeping bag shells are thin nylon or polyester that can melt.

NEMO recommends a gentle cycle with a two-rinse option in cold water in an oversized, front-loading commercial machine with no agitator, then tumble drying on low heat in an oversized dryer with clean tennis balls. It warns against bleach, ironing, dry cleaning, high heat, and drying a wet bag while it is bundled up. Big Agnes says sleeping bags often need 2 to 4 hours and multiple cycles to dry, and to stay with the dryer so you can fluff the bag every 20 to 30 minutes.

If your home washer is a standard top-loader, take the bag to a laundromat. The same goes for any washer you cannot fit the bag into loosely. For more on keeping your own machine in good shape, see our front-load washer cleaning guide.

Can you hand wash a sleeping bag in the bathtub?

Yes, and it is gentler, but rinsing and wringing a heavy wet bag is hard work.

• Fill the tub with lukewarm water and the dose of down or gear wash for hand washing on the bottle.
• Submerge the bag, press the air out, and knead it gently for a few minutes. Let it soak about an hour.
• Drain, refill with clean water, and press and squeeze until no suds appear. Expect three or more rinses.
• Press water out by rolling it from one end with the drain open; do not wring or twist it.
• Lift it out in a bundle and dry it in a large dryer as above, or lay it flat in the shade for several days, fluffing often.

How to store a sleeping bag after washing

Store it loose in a large breathable sack or hanging in a closet, never stuffed in its compression sack.

NEMO says long-term compression damages the insulation and loft, and to store the bag in a cool, dry, dark place. Big Agnes suggests washing a bag before seasonal storage if it saw heavy use. A sleeping bag liner keeps the bag cleaner between trips so you wash it less often; washing a liner is as easy as washing a sheet. For bedding you sleep on at home, see our mattress cleaning guide.

Mistakes to avoid

• Washing it in a top-loader with an agitator, which can tear the baffles inside.
• Using too much regular detergent, which leaves residue that makes down clump.
• Adding fabric softener, bleach, an oxygen booster or a wash-in waterproofer.
• Drying it on high heat, which can melt the shell fabric.
• Storing it while it is still slightly damp, which leads to mildew and a sour smell.
• Keeping it in the compression sack between trips, which flattens the insulation.