Sleeping Bag Guide
The Insulation in Sleeping Bags

Sleeping Bag Insulation

High technology has struck again. This time, the technology has struck the sleeping bag market. Not too many years ago, sleeping bags were all made from goose down or polyester. Today, however, in an effort both to improve sleeping bag insulation and to dazzle consumers about their products, manufacturers now use a multitude of "cool" sounding names for sleeping bag insulation.

Since anyone who is searching for a sleeping bag will inevitably stumble across this terminology, I thought it would be helpful to prepare this guide that explains the terminology about the different types of sleeping bag insulation available.

So lets get started. And at the bottom of the page I'll recommend what types of insulation you might want to get for differing camping situations.

The Five Primary Types of Sleeping Bag Insulation

There are five major types of sleeping bag insulation a consumer will stumble across when searcing for a sleeping bag. While other insulation types DO exist, these five are by far the most common.

Goose Down

Goose down insulation is the classic insulation used in sleeping bags, and, despite all the technological advances, still the most efficient insulation around. Goose down provides the most warmth for the least bulk, allowing for very warm sleeping bags that are in very, very small packages.

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However, to muck things up for consumers, sleeping bags frequently contain terms like this - "600+ fill goose down" or - "900+ fill goose down" or something else along those lines.

When you see this, don't be too bedazzled. All it is telling you is how much goose down is actually put in the bag - or the "fill rating" as I call it. The higher the number, the more goose down insulation is put in the sleeping bag. And, at least theoretically, the warmer the sleeping bag will be. Most three-season sleeping bags will have a "fill rating" of at least 600. And four season down sleeping bags will have a fill rating of around 900 - 1000 if those bags are designed for true sub-zero weather use.

Now, the only problem with goose down insulation is that it is USELESS when wet. And it can take forever to dry. Thus, if you think you have a risk of getting your bag wet (such as being out on a float trip), do NOT get a down bag. Get a synthetic instead!

PolarGuard/Polarguard 3D/PolarGuard Delta

Polarguard is considered the "premiere" synthetic insulation. There are actually three primary varieties of Polarguard available.

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The first, known simply as PolarGuard, was a bit on the bulky side but still works very well - which is why you see it still used in many sleeping bags today. And at the time of its introduction, was a huge leap over the synthetic materials then on the market.

Later, Polarguard 3D was introduced, which packed the same insulation ability but reduced the weight and bulkiness of the sleeping bag considerably.

And then recently PolarGuard Delta came along which is a significant improvement over older Polarguard insulation. Polarguard Delta took PolarGuard 3D and made the bag significantly less bulky, while at the same time improving the insulating abilities by around 10%. Currently, most high quality three-season synthetic bags are made of PolarGuard Delta (including mine).

One superb thing about all varieties of PolarGuard is that, being synthetic, it dries out amazingly quickly. Even better, the bag does NOT lose all insulation abilities once wet. Indeed, the simple act of sleeping in a wet sleeping bag will actually dry it out! And lastly, bags made out of PolarGuard are very easy to take care of. Simply wash in cold water in a front load washer. Then tumble down on low heat for about 10 minutes. And presto - your bag is ready to go.

For this reason, if there is a risk of you getting your bag wet, get a PolarGuard Delta sleeping bag.


Quallofil is made by Du Pont. Quallofil is used both in sleeping bags and in many insulated jackets. The problem with Quallofil with sleeping bags is that it is a bit on the heavy and bulky side, which is why you rarely see it anymore on the higher end (and lighterweight) sleeping bags.

Hollofil & Hollofil II

Hollofil was once upon a time a great insulation, but has fallen way behind PolarGuard. Today, it is used in bargain basement type sleeping bags. Works well for camping in the backyard for the kids, slumber parties, whatever. But definitely not even close to the being the first choice for true camping, let alone backcountry, use. Sleeping bags with Hollofil lack good insulating ability for backcountry use, are heavy and quite bulky.


Thermolite is a great insulation for jackets as it isn't "puffy" like goose down or quallofil is. Unfortunately, it makes for a poor choice of insulation for a sleeping bag. In a sleeping bag, for outdoor use, you want the insulation to be "puffy" as the air pockets retain the heat. By and large, the only place you'll find thermolite insulation used in sleeping bags is in bags that cost $50 or less. These bags are best used for slumber parties, backyard camping, whatever. Don't even think of taking them to Montana to camp outside with - you'll freeze even during the summer.

Which Insulation to Get?

That is the million dollar question, isn't it? Thankfully, this question is very, very simple. Let's look at what works best for different types of camping.

Four Season Bags for Winter Camping - Easy answer. Get a goose down bag. The risk of getting the bag wet is very, very low. And the less weight and bulk of a goose down bag is worth all the money you'll spend.

Shop & Compare Winter Sleeping Bags

All Purpose Three Season Bags - Another easy answer. By "all purpose", I mean that the bags could be used on float trips or used in wet climates. For this, you definitely want a synthetic sleeping bag, since if the bag gets wet it will dry out quickly.

Shop & Compare Three Season Sleeping Bags

Lightweight Three Season Bags - This is a bit tougher. If you really, really need an ultra-portable bag, then goose down is the way to go. However, you need to be extra sure never to get it wet.

Shop & Compare Lightweight Sleeping Bags

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