Storing bags compressed

[Buckshot85]

What actually does it harm to store a sleeping bag compressed?
I’ve got an older Marmot Chinook mummy bag that I forgot about for around 15 years.
Yeah, I know. Let’s just get past that.
I have no idea on it’s original rating. I need a bag for wall tent hunt next fall and maybe a sheep hunt in a few years.
Bag looks great. No visible issues.
So what goes bad?

 

[Superdoo]

Usually the down will retain the compression and won’t loft. Throw it in the drier with some tennis balls.

 

[BuckeyeRifleman]

From what I understand, as long as the down is dry and clean when it was compressed it should loft back up with agitation from tennis balls in the dryer (low or no heat.)

Now compressing a wet bag for any length of time is a no no, as is long term compression of a synthetic bag.

Let me preface this with the fact I am not an expert on this, but this is my understanding after reading FAQ’s from various manufacturers websites. That said I still don’t store my down bags compressed... But stick that old bag in a dryer with some tennis balls and see what happens. It should come back to life.

 

[orionsbrother]

What they said. Not ideal, but if not packed damp, probably not a horrible loss of temp rating if you tumble in drier on air with tennis balls or similar.

 

[Buckshot85]

Wasn't damp at all when stored. I'll try the tennis balls and fluff it in the dryer.
Appreciate, guys.

 

[Dos Perros]

Storing compressed will absolutely wreck a synthetic bag.

 

[Buckshot85]

Well I though my older Marmot Chinook was down but don’t know for sure.

 

[skierhs]

The only real way to tell if your bag will be decent enough to use is uncompress it and see how the insulation reacts. If the insulation is lumpy you'll have a bad time. If the insulation doesnt bounce back, then you'll have a bad time. Seeing that you may be going on a sheep hunt I wouldnt risk it and would buy a new bag for the weather you're going to face. If your wall tent has a stove then you can make it work but you may not get much sleep as you'll be the one stoking the fire throughout the night.

Another tip is hang the bag in the closset and see how the bag comes back to life. Frankly, i dont have much hope for a bag that has been compressed for 15 years but i've seen crazier things.