Sleeping Bags A Complete Guide
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The best way to keep warm while camping is with a proper sleeping system. Your sleeping system is a sleeping bag, your sleeping pad, and your clothes. A good sleeping bag is the most important element of your sleeping system.
Every week, starting in late fall and continues all of the way through to late spring, in any online camping community you will hear this question:
“We got so cold last night. How can we be warmer?”
Beginner campers think that their tent is going to keep their warm.
A tent is not designed to keep you warm. In particular, if you are sitting or lying down on the ground.
That’s because according to the physics of heat transfer.
There’s a great article on this from Penn State University.
Our body loses heat through 3 mechanisms.
The first is radiation. This is the primary way we lose heat.
While we are alive, our body acts like an infrared furnace. This is needed so that our organs can function. But if we don’t have enough insulation around us such as four solid walls or a sleeping bag, the heat is lost.
Then there is conduction. This is where hot and cold areas (such as our bodies and the ground) attempt to achieve equilibrium. And if you are sitting directly on the ground, Mother Nature is going to work extra hard at trying to achieve equilibrium.
Finally, there is convection. Convection is how hot and cold fluids attempt to achieve equilibrium. While out camping, convection is why the wind feels cold or hot as it blows across our bodies.
And according to a study at Kansas State University, we lose most of our body heat by just radiating heat. And it’s the job the sleeping bag insulation to keep that heat trapped close to our body.
Thus you need a sleeping bag to go camping to keep you warm. After the sun goes down it often gets cold outside. Even if you are camping in the desert. This is particularly true if you are camping in the mountains or during the winter.
The rest of this short guide will show you how to choose a sleeping bag.
WHAT TYPE OF CAMPING WILL YOU DO
If you want to know the secret to the fastest way to start an argument in a camping group on Facebook, give an opinion on how you think people should go camping.
If you have never witnessed this, it’s never pretty.
This is unfortunate because as someone summarized in a group, campers in real-life are the nicest people when together.
But in an online forum, they can become real jerks in these discussions.
At Camping Forge, we encourage all forms of camping. Cowboy, backpacking, tent, RV, and cabin resort camping are all encouraged.
Because if you sleep well, then you will have more fun overall.
What prevents people from camping more than anything is people not wanting to poop in the woods using moss for toilet paper and uncomfortably sleeping.
But when choosing your sleeping bag it is important to be clear about the type of camping that you will be doing.
And in what season.
According to Outdoor Participation Report 2019, while there were over 41 million Americans who went camping, only 10 million Americans did a backpacking trip.
Which means, most likely, you are going to be car camping.
Car camping means that you will be able to bring everything in your vehicle. And you won’t have to carry your gear very far.
The benefit of car camping for choosing your sleeping bag, is that you don’t have to look for the smallest packing and lightest bag. You can pretty much just choose one based on comfort.
Meanwhile, if you are going to go backpacking, then you will want to look at the weight and pack size of the bag. Currently, the trendy thing is to find the “most ultralight” gear possible. But I believe you can go too far.
There won’t be much fun in doing a week-long backpacking trip if you’re shivering every night.
Finally, what weather will you be camping in?
Most people camp from late spring through early fall.
This way you don’t have to worry about the worst of cold weather and snow.
Thus you can look for a 3-season sleeping bag.
If you do intend to do true winter camping where you expect sub-zero temperatures then you will want to look for a true winter or arctic sleeping bag.
WHAT SHAPE AND SIZE
Everything with a sleeping bag is based on your own personal requirements. And the shape of a sleeping bag is no different. There will be things you like and don’t like about each.
The rectangle bag is the shape people are most familiar with. And will be the closest to traditional blankets. You can even unzip the bag completely and use it like a large blanket. People like rectangular bags because they give you the most room.
And you can purchase bags that are designed to be zipped together. This is perfect for couples who want to sleep together in a tent.
Or if you’re a mom and a little one needs to snuggle after a scary campfire ghost story.
But, because rectangular bags are large, they often don’t fold up well. And are rarely the preferred option for backpacking.
If you want a compromise between a rectangular bag and a mummy bag then you can look for a tapered bag.
A tapered bag will narrow towards the feet.
Because it tapers, it will be warmer because there’s space for the heat your body generates to escape to. While it has less freedom of movement than a traditional rectangular bag, it will be more than a mummy.
I remember looking at the Boy Scout gear catalogs as a kid and always wanting a mummy bag.
I think mummy bags were for serious explorers.
Mummy bags are great for backpacking because they roll up small and are lighter.
These bags fit tight around the body so that you will look like a mummy from a horror movie. Mummy sleeping bags also have a hood that fits around your head to maximize the amount of trapped body heat.
Mummy bags restrict movement. A top complaint of sleeping in a mummy bag is that if you need to roll over, you have to flip the entire bag with you in it.
But they are the warmest sleeping bags. And because of their light-weight and small size are perfect for backpackers.
Another variation on the sleeping bag is the camping quilt. A camping quilt is like a backless sleeping bag.
A camping quilt will have a foot box. This is because when we’re lying down, we are not pumping as much blood to our lower body. And thus we will be colder in our feet.
A camping quilt will also have straps designed to keep it attached to your sleeping pad. The straps are there so that if you roll over in your sleep, you keep covered up.
A sleeping bag can also be found in three common sizes.
There are children sleeping bags. Which are good for young children. But once they’re around 9 years old, you should consider buying an adult sleeping bag for them.
A standard size sleeping bag is designed for the average adult.
However, if you are like me and very tall (I’m six foot four inches), then you will want to look for an extra-large bag.
You can also find other amenities on your sleeping bag such as a draft collar. A draft collar is designed to keep warm air from escaping out of the top of the sleeping bag.
Many now also include a gadget pouch. This is where you can stash something like your earphones or Air Pods when you’re ready to go to sleep.
WHAT TYPE OF INSULATION
The primary purpose of a sleeping bag is to keep you warm while camping or backpacking.
While researching for this guide, I came across a study from Kansas State University about sleeping bags. According to this study, we lose twenty-five percent of our heat from our breathing and sweating as we sleep.
But the remaining seventy-five percent of the remaining heat is lost through the dry heat our body generates.
Your sleeping bag’s insulation is designed to reduce the amount of dry body heat you lose in the night. According to Scientific American, the essential principle of insulation for warmth is to use air pockets to keep warm air trapped next to our bodies.
Insulation works because air is not a good thermal conductor.
This is how sleeping bag insulation works.
It keeps the warm air that your body generates next to your body.
However, when we lay down on the bag, it will compress those air pockets. And that’s going to reduce the insulation capability of our sleeping bags.
This is why when we plan to keep warm in a tent, we don’t just think in terms of a sleeping bag.
But a complete sleeping system. Your sleeping system will include your bag, the clothes you wear, and a sleeping pad. According to the Kansas State study, the proper sleeping pad made the biggest difference in improving the insulation of a sleeping bag.
And when we lay down in our bag, the sleeping bag insulation gets compressed. Thus it does not do as good of a job at retaining our body heat.
A good sleeping pad will provide a thermal barrier. And we will cover how to choose one later in this guide.
Now that we understand how insulation works, let’s look at our options.
There are two broad types.
Down and synthetic.
Down insulation is a natural material.
It comes from the feathers of ducks and geese. It’s the feathers that are closest to the body and is among the best natural insulation.
One of the reasons why people love down insulation is that it provides greater warmth at less weight. And it compresses very tightly. This is why down sleeping bags and coats are prized among backpackers where every ounce of weight matters.
However, there are three downsides to the down sleeping bags.
The first is the cost.
Down sleeping bags are more expensive.
Down also loses most of its insulating power if it gets wet.
And finally, people can be allergic to the down itself.
Synthetic insulation is the opposite.
It’s cheaper than down.
It can keep much of its insulating power if wet.
And it’s hypoallergenic.
One more benefit to a synthetic sleeping bag over a down sleeping bag is washing the bag.
I listened to Dixie over at Homemade Wanderlust talking about the gear she used to hike the Appalachian Trail. And she mentioned that you can’t just wash your down sleeping bag in each town on the trail.
Meanwhile, you can wash your synthetic bag more easily. And we will cover more about how to care for your sleeping bag later in this guide.
But remember, a synthetic sleeping bag is often heavier and doesn’t compress as well.
UNDERSTANDING TEMPERATURE RATINGS
There are lies.
And sleeping bag temperature ratings.
Ok, it’s not that bad but it is important to understand how sleeping bag temperature ratings are determined and what their limitations are.
When shopping for a sleeping bag, you will notice that there is a temperature rating in the bag.
In 2005, Europe created a standard rating system for sleeping bags. And in 2017, the ISO organization created an international standard. These standards allow you to compare sleeping bag temperature ratings with the knowledge they are the same between bags.
However, while there is a standard rating system, it is not perfect.
For two simple reasons.
One, the rating system is based on a complete system and not just the sleeping bag.
Two, everyone sleeps a bit differently.
The complete sleep system assumes that you are wearing a base layer, a sleeping bag, and a sleeping pad.
In the next chapter, we will discuss how to choose a sleeping pad. And later in this guide, we will discuss how to properly dress for sleeping in a sleeping bag.
In general, women sleep colder than men. However, everyone has different temperatures at which they will fill comfortable. My female work colleague K who grew up in Minnesota is much more tolerable of cold weather than my wife J who is a native Texan.
Another factor to understand is that the coldest rating in a sleeping bag is the lowest temperature the bag is designed to keep you alive with the complete sleep system.
This is why the most important takeaway from this chapter is to look for a bag that is rated for at least ten degrees colder than your planned coldest temperature. You can always open up the bag to let more cool air in or ditch the bag completely if needed. But it is much harder to make a sleeping bag warmer.
CHOOSING A SLEEPING PAD
As we explained earlier, a sleeping bag alone is not enough to keep you warm. The bag is one component in a complete sleeping system. The sleeping system includes your bag, what you are wearing and a sleeping pad.
According to research done by Kansas State University, the most important item to improve the warmth of your sleeping bag is your sleeping pad.
This is because by elevating your body off the ground reduces the amount of heat that you will lose from conduction with the ground. Because even in temperatures that you would be warm enough in a long-sleeve shirt such as late winter, the ground can still freeze.
There are 3 basic types of sleeping pads for modern campers.
The first is the foam pad. A foam pad will look like a yoga mat. They may have a piece of reflective material on one side which can be used to increase the warmth of the sleeping pad by bouncing your body heat back up at you.
However, a foam pad is generally only comfortable for back sleepers. And they can only be rolled up so you would have to attach them to the back of your pack. But you do not have to worry about them developing a hole and deflating on you.
The second type is the inflatable sleeping pad. Based on my anecdotal research, these are now the most common type of sleeping pads. Inflatable pads are more popular because they are more comfortable and they pack down smaller.
However, they can develop leaks. So make sure you have a patch kit or duct-tape with you to patch any holes that you find.
You may also wish to use an air mattress instead. In particular, if you are car camping with your significant other.
Air mattresses are similar to inflatable sleeping pads.
While, you can find online stories of people saying that they think air mattresses are not warm enough, I have a feeling they are blaming the air mattress but it was really the sleeping bag.
Because a properly inflated air mattress is going to give you several inches of space off the ground. And as we discussed in the chapter on insulation, air is a poor thermal conductor. Thus it should be enough insulation to keep you from losing body heat to the ground.
When evaluating sleeping pads, they should have an R rating attached to them. An R rating is a standard for insulation.
You will want an R rating of 4 or higher to give you maximum warmth in cold conditions.
Finally, on your trip, make sure to bring along a couple of 6 Mil contractor bags. In the worst case, if your sleeping pad were to develop a leak that you cannot fix, you could stuff leaves and grass into a contractor bag to improvise a sleeping pad.
From a camping group I’m in, someone said “ A 3” thick foam mattress (30” wide and 6’ long) at Home Depot for $20 is more expensive, but lasts longer, is warmer in winter, and is far more comfortable.”
As discussed in previous sections, your sleeping bag is part of a sleeping system. The two other components of your sleeping system are your sleeping pad and what you wear. The complete sleeping system is designed to enable you to keep warm and comfortable. And you have to pay attention to the entire system because it is difficult to make a sleeping bag warmer unless you prepare ahead of time.
It is important to understand what to wear to sleep while camping. In particular, when it is cold outside. And it can get cold enough to cause a threat of hypothermia, in many places for most of the year.
This is because, according to the Mayo Clinic, hypothermia is when your body temperature starts to drop below 95 F. Thus, even here in North Texas, in late March, you could catch hypothermia when a spring cold front comes through. Bringing rain and dropping our temperature from 81 down into the 40s overnight.
This is why when you’re camping or backpacking make sure to always have a sleeping outfit. And pack it so that it will stay dry.
Your sleeping outfit should be a synthetic top and bottom like your base layer. You want something that will not trap sweat next to your body. Because you can develop hypothermia even in a warm sleeping bag that way.
You also want to put on a warm pair of wool socks. Wool is a great insulator even if they get wet. Put on clean socks when you go to sleep.
Finally, you can put on a hat if necessary.
HOW TO INCREASE THE WARMTH
Everyone who has ever climbed into a cold sleeping bag has wondered how to make it warmer. And every camping forum is filled with stories of people who went camping with a sleeping bag that wasn’t rated for the temperatures they were in.
Besides making sure that you have a properly rated sleeping bag, a good sleeping pad and are dressed appropriately there are some things you can do to make your sleeping bag warmer.
A common hack you will hear about is to place a water bottle into your campfire to warm it up. Then wrap the bottle in a shirt or rag and place it in your sleeping bag to warm it up.
Another option is to use a sleeping bag liner.
Sleeping bag liners are like sheets you put into your sleeping bag. They add an extra layer of insulation using similar properties to your base layer. And they can add significant amounts of warmth to your bag.
For example, a synthetic liner could add over 20 degree F of warmth to your sleeping bag.
And by preventing your body’s oils and sweat from coming into contact with your sleeping bag, it will extend the life of your sleeping bag.
Liners are light and affordable and pack small. Thus you should look at buying a sleeping bag liner.
Besides sleeping bag liners, you could also bring along blankets or quilts as well.
There are also additional hacks to your tent that you can do to improve its overall warmth.
Technically, you there are heaters (such Mr. Buddy) that you can use in a tent. And in northern climates, you will find people who purchase canvas tents with a chimney so that you can setup a wood stove or campfire.
However, many people don’t feel safe with this type of setup. Because of the dangers of fire or carbon monoxide poisoning.
There are safer options that can help.
You can place rugs, moving blankets or foam-tiles designed for children’s playrooms on the bottom of your tent.
Another trick you can do is to use Reflectix or an emergency blanket attached to your rainfly. Make sure the shiny side points to the tent. This will reflect your body heat back into the tent. Some people even wrap an emergency blanket around their sleeping bag. But it’s noisy and will sound like you’re sleeping in a potato chip bag.
HOW TO CLEAN
After every camping trip, set them outside and shake them out. This way you can clean them of any dirt. And to make sure nothing else rode a ride home in them. While I doubt a snake or bear would hike a ride in your sleeping bag, it’s possible insects will hitch a ride. This could be ants. Or spiders. Or beetles.
I remember the first time I ever got stung by a wasp, it was while rolling up my sleeping bag. It was a Mud Dauber wasp. Proving its a myth to think those things don’t sting!
If there’s any dirt, mud or grime on your sleeping bag, you can use a damp rag to clean the shell.
However, periodically a sleeping bag will need to be washed. Make sure that any sleeping bag you purchase, can be washed in a washing machine.
Once you have done then make sure that you follow the manufacturer’s instructions. Though in general, you will need a front-loading washing machine and then you will need to air dry the sleeping bag to protect the insulation.
You can find more tips on cleaning a sleeping bag in this article at Good Housekeeping.