We posed your question to Big Agnes rep Carl Johnson. Here’s what he had to say:
How long your bag stays cozy depends on how often you use it, how hard you are on it, and how you store it.
“Down packs out over time, just like a down pillow or comforter. After a year or two of use, it flattens out and is a lot less fluffy,” Johnson says. When your down looses fluffiness, it looses insulation power because doesn’t trap as much warm air to keep you toasty.
There are a few things you can do to help your down bag keep its heat-retaining abilities. First, don’t store your bag in a tight stuff sack. Your bag needs to breathe, so store it in roomier sack. Second, since your bag is already having issues, you can help rejuvenate it with a wash-and-dry. Check your bag’s label for washing instructions. Most down bags can be washed on the normal cycle with mild, or specially formulated down soap. Next, put it in the dryer with a few tennis balls and dry on low heat. “The tennis balls basically punch the down back into life,” Johnson says.
If that doesn’t help, your bag may be too old to rescue. “Down feathers are basically proteins that break down over time,” Johnson says. Unfortunately, there’s no exact science for determining when your bag will bust. “Higher quality downs, which hold loft well, break down quicker, so a 900 fill down bag will become essentially a 700 fill down bag within a few years from normal use. It won’t have that same warmth rating after a couple years of use.”
Got a synthetic bag? The rules are the same. “Just make sure you basically use low or no heat in the dryer, because synthetic materials will melt in the heat,” Johnson says.
THE BOTTOM LINE: Your sleeping bag can lose its heat rating over time. Letting it breathe in storage, and throwing it in a dryer with some tennis balls can help breathe life back into a limp bag. If you’re still cold, it might be time for a new bag. Check out some of our favorites here.