Sleeping bag manufacturers fill up their bags to the optimum fill point. This is the point where additional filling starts to add less warmth relative to its weight. It’s both lighter and cheaper to increase the size of the fabric baffles.
The baffles should be just barely filled up with down, leaving enough room for the down to be fluffed up. There’s a fine line between finding optimum warmth and adding additional weight. Does overstuffing a down sleeping bag add additional warmth?
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Should You Overstuff a Sleeping Bag?
I always add additional insulation to my sleeping bag. Overstuffing a sleeping bag both increases the temperature rating of your bag and rejuvenate an old bag that lost its loft.
Check out my post on adding down filling to a sleeping bag.
What Does Overstuffing a Sleeping Bag Mean?
Overstuffing is exactly what it sounds like. You take additional down filling and stuff it into your bag in an attempt to increase warmth. You’re trying to stuff the bag with additional filling to go above the temperature rating.
Does Overstuffing Make Your Sleeping Bag Warmer?
Even though overstuffing a sleeping bag isn’t optimally efficient it does add additional warmth. The only problem with overstuffing a bag is you start to compress the filling.
When you compress the filling you get less warmth for every extra oz of stuffing you add. You’re getting additional warmth at the cost of added weight.
I’ve found that adding 1oz of down filling to my sleeping bag adds about 2.5 degrees to its temperature rating. Stuffing about 8oz of down into a bag will add about
Some Experts Claim Overstuffing Doesn’t Help(They’re Wrong)
Some experts in the industry claim that overstuffing a sleeping bag won’t noticeably increase the warmth. They say that down provides insulation by trapping air in the open space between the plumes. So, therefore, loft height is what determines warmth rather than density.
This line of thinking makes sense in theory, but it’s dead wrong! R-Value will always increase when you overstuff a sleeping bag.
Adding additional insulation to a bag will always make it warmer. The added compressed down will add warmth, but it’s less efficient for the additional weight added.
Overstuffing Makes Down Less Likely To Move
Overstuffing a bag shouldn’t change the loft all that much, but it will help cluster the down. The additional filling helps stabilize the down clusters so it won’t shift throughout the bag. Your down won’t migrate throughout the bag to the point where it needs to be redistributed.
Overstuffing Slows a Bags Degradation
Overstuffing a sleeping bag significantly increases the lifespan of a sleeping bag. As a bag loses its loft over time the extra down filling will make up for the heat loss due to compression.
Does Overstuffing Compromise Your Bag(In Any Way)?
The real question is, does adding additional stuffing compromise the performance of your sleeping bag? Of course, it will add a few ozs of weight, but are there any downsides?
Personally, I’ve never noticed any downside to adding additional insulation. You’d be surprised at how much of a difference 5 Degrees makes on a cold winter night. It could be the difference between shivering all night and getting a good nights sleep.
You Can’t Fluff Up The Down
Think about it for a second, if you fill-up the baffles in your bag it’s going to be hard to fluff everything up. When you want as much loft as you can get, compressed down won’t be as warm as the equal weight in a larger baffle.
Overstuffing the bag won’t allow you to get as much loft as you would with a bigger baffle(aka lower temperature bag). You definitely want some overstuff to combat compression when you’re bag inevitably loses loft, but avoid going crazy with the additional filling. That being said, it does feel much better to sleep in an overstuffed bag, but you will pay a small weight penalty.
It Will Make Your Sleeping Bag Heavier
Obviously, adding additional insulation will make your bag a little bit heavier. You need to make sure the additional weight is worth it. Sometimes you’re better off purchasing another bag liner or a thicker sleeping pad.
Sea to Summit’s Extreme Bag Liner (On Amazon) adds 25 degrees to your bags temperature rating at 14oz. It might be worth upgrading if you’re using a cheap bag liner.
