How Down Sleeping Bags Lose Warmth ( and how to prevent it )

When properly maintained and fluffed, down sleeping bags will maintain their warmth for years. However, over time, the natural compacting of down can cause it to not retain heat as effectively as it did when new. Also, different factors such as getting wet can cause down sleeping bags to drastically “lose their warmth”. This is because water will cause clumping and clumping will cause down to not trap heat effectively.

There are many different types of sleeping bags available today. Made with various materials and different types of fills, each one has their benefits and drawbacks. Their temperature ratings and costs vary greatly.

One of the best sleeping bag insulators is down. Prized for its warmth, durability, and weight down makes an excellent fill substance. But can a down sleeping bag stand up to the test of frequent rugged camping trips, especially in harsh conditions, or will it lose its warmth? The strongest determining factor is water.

Down is considered nature’s insulator, though it has made its way into many manmade products including pillows, jackets, and sleeping bags. Commonly thought to be composed of feathers, down is actually the fine filaments found under the feathers of waterfowl.

Humans have not yet been able to replicate the insulation properties of natural down. Man-made synthetics remain less insulative and less warm than geese or duck down. One Marmot brand down bag with an 800+ fill power can withstand temperatures as cold as negative forty degrees.

Typically the chosen bird species are geese, although some down is sourced from ducks. Under their exterior water-resistant feathers is their fine, fluffy, and insulating plumage; this is down.

Down keeps waterfowl (and humans) warm by trapping air and working as an insulative barrier without being heavy. The loftiness of the feathers holds pockets of air in place, these air pockets are warmed by your body and then maintain their heat to insulate you inside your sleeping bag. The more down fill-power an item has, the more insulating and warmer it will be.

Fill power simply means the measure of downs fluffiness, or more scientifically its “loft”. The more fill power down has, the more air it can trap, and therefore the more insulative and warm it will be. Fill power generally ranges from 300 to 900.

Another benefit to down fill is its durability and compressibility. Down fill can be compacted in order for your sleeping bag to be stored or carried easily. The higher the fill power, the fluffier it is, this means less down has to be used; resulting in a lighter bag that still retains excellent insulative capabilities.

Down sleeping bags are usually quite long-lasting and are perfect for campers who frequently camp in dry, cold, and desire a lightweight and compact bag.

One drawback is the cost, down can be expensive. Geese down has become more expensive, resulting in some manufacturers turning to duck down or fill that is a mix of down and feathers. However, due to its durability, this long-lasting bag could be considered an investment for the frequent camper.

What Will Cause Down to Lose Its Warmth?

Down has one other significant drawback aside from the cost. It is not equipped to handle moisture well. Soaking your down sleeping bag can be a recipe for disaster.

Unlike the top feathers of birds that shed water and protect the down found underneath, the fill in your sleeping bag will quickly become saturated if it gets wet. Once waterlogged, the down becomes a very poor insulator, resulting in a chilly sleeping situation.

When down gets wet, it’s fill power becomes null and void. The down will begin to clump and lose its ability to insulate. This means that the sack will no longer be warm, but instead a bag full of heavy wet feathers. That is why waterfowl have a protective barrier of water-resistant feathers over-top of their down plumage.

Additionally, down takes a long time to dry. If you are caught in a downpour with your sleeping bag on day one of your trip it could spell the end of your camping expedition. So what do you do if you are stuck with a wet bag?

There are many methods you can try to dry out your sleeping bag. If it is only wet in one area you are much better off than if it is completely soaked.

First, try to break up the down clumps as much as possible. Spreading out the down will help it to dry faster and retain some of its loft. Next, you should try to heat the bag.

Before heating, check the shell to make sure that heat can be applied without melting it. If so, use a camp stove, the fire, or even a hairdryer to cautiously and slowly warm the bag. Down not get your bag too close to the heat source as it may catch on fire.

You can also use natural resources to dry and warm your bag. Consider opening it up and laying it in the sun or hanging it on a line or tree branch to dry in the wind.

If it is night, and you have no choice but to sleep in the wet bag you may want to put cotton blankets or clothing on top to draw out some moisture. Sleeping with nothing on inside the bag can also allow your skin to warm the down.

How to Prevent Warmth Loss

The most important thing is not to get the bag wet. Try to protect your sleeping bag from rain, rivers, and any other damp situation. Store the bag in a dry area in a pillow liner or mesh bag.

Properly Care for Your Bag

Occasionally, after consulting with the manual or manufacturer, it can be beneficial to “re-loft” your down. You can take it to a laundromat and use a commercial strength dryer or have it professionally laundered.

Be careful attempting to wash or clean your sleeping bag at home. Some detergents or fabric softeners can contain oils that can fundamentally alter the nature of the down. If these oils adhere to the down plumage they can make them less lofty, insulative, and warm.

Be sure to air out your down bag in between camping trips, whether you use a shell/liner or not. If you are camping in a humid or tropical environment, the down can soak up moisture from the ambient air even if you are inside a tent. However, this will usually take quite a long time.

Before storing your bag after returning from your trip, it is a good idea to hang it out and make sure it is completely dry. Then store it in a bag that will not trap moisture, such as a mesh, and keep it in a dry place.

Choose a Treated Down

If you want to prevent any accidental water incidents from the get-go, consider a treated down. Hydrophobic down is treated to be water-resistant, typically with a compound called DWR. The down is coated with a chemical similar to the one used on waterproof boots or jackets in order to make it water repellant.

These coatings will likely eventually wear off, so it is not a good idea to repeatedly soak your bag. Additionally, sleeping bags with hydrophobic down may cost a bit more than traditional down bags.

Select a Water-Resistant Shell or Liner

To prevent moisture from gaining access to your down, you can also choose a sleeping bag with a waterproof or water-resistant shell. Waterproof liners that go on the outside of your sleeping bag are also available, but these have a higher likelihood of trapping perspiration and making you damp from the inside out.

Water Resistant down bags typically have shells treated with DWR. As mentioned before, the DWR can wear off after repeated use. Therefore, you may have to reapply at home with a DWR spray coating.

It is important to note that these sleeping bags are usually not considered “waterproof”. Down bags typically have a great deal of baffling, or material sewn into compartments. Most manufacturers do not tape or seal all of the baffling seams meaning water can still seep in.

Overall, choosing a bag that has a water-resistant shell or using a water-resistant covering can affect the bags breathability. This may result in you becoming too warm and perspiring in your sleeping bag.

Patch Any Holes

Down is known for quickly losing fill if you have even the smallest hole or tear. It is important not to pull any feathers or down you may see poking out, but instead try to push them back in. If you do have a tear there are a few methods you can try.

In the backcountry, one of the most popular down patches is duct tape. However, you should plan on the duct tape being a permanent solution as removing it could exacerbate the solution.

If you want to try and more properly repair your down bag, consider using adhesive pre-cut patches. Most craft or sewing stores have them readily available and they can be carried along with you on your camping trip. Just be sure to select a self-adhering patch instead of one that has to be ironed on.

With proper maintenance, care, material selection and a cat-like avoidance of water, you should be able to maintain your down sleeping bags warmth for many years to come.

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Rickie Arms

Hi, I'm Rickie Arms, owner of Glampingorcamping.com. I am so invested in writing the best and most informative articles for you that I went out and bought a travel trailer just so I could write about it for you. I spend just about all of my off time both camping and glamping so I can share everything I have learned and will learn with you. I have spent my whole life camping and over the last 10 years, I have spent a large amount of time checking out glamping experiences with my wife and kids as well. Thank you for coming by and we hope to see you back here getting great information in the future. Rick Arms-

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