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.

Contents of this article include:

The Two Types of Sleeping Bag Insulation – Goose Down and Synthetic

To begin, let’s define some terms.

Goose Down Insulation

What is goose down? Goose down insulation is “natural insulation.” That is, the sleeping bags insulation consists of insulation—called under plumage—found beneath the feathers of ducks, geese and other waterfowl.  Thus, goose down insulation does not consist of feathers. Instead, it is the waterfowl’s insulation below the feathers that is used for sleeping bag insulation.

Goose Down Jargon Alert!

Goose down 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, known as the “fill rating.” 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 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.

Synthetic Insulation

Synthetic insulation, by contrast, is a lab creation. The insulation does not consist of natural insulation found on animals but instead consists of other, various materials. Thus, there is no “natural” insulation found within a synthetic sleeping bag.

Important note: there are numerous types of synthetic sleeping bag insulation—there is no “one set type” used. Each type of synthetic insulation has its “goods and bads,” which are described further down in this article. Just note that synthetic insulation in a sleeping bag means “artificial” insulation—and not “natural” insulation.

Benefits and Drawback of Goose Down and Synthetic Insulation

The age-old question among backpackers is whether synthetic insulation or goose down insulation is better. And the answer is-it depends. By that, it depends entirely on where you plan to camp, what temperatures you’ll be camping in, and how you’ll be getting there.

So what’s better? Goose Down Insulation or Synthetic Insulation? Let’s examine these two types of insulation in a couple of key real-life metrics that any camper or backpacker will find of interest, leaving any “technical specs” for another day.

Weight & Bulk

In terms of pure “packability,” goose down always wins. Of all the sleeping bag insulations available, goose down insulation packs down the smallest when compared to a synthetic sleeping bag rated to the same temperature.

For example, if you have a 25-degree rated goose down sleeping bag, it will be lighter and pack down into a smaller package than a 25-degree rated synthetic sleeping bag.

However, synthetic sleeping bags have made great strides in recent years in closing the “weight and bulk gap.” For three-season use, the weight/bulk differences between a quality goose down bag and a quality synthetic bag is not great. Modern, high-quality sleeping bags today compress down into a package barely larger than a goose down bag, while only weighing about 4-6 ounces more.

For winter use, however, gooses down bags are dramatically smaller and lighter in weight. The extra insulation needed for winter sleeping bags dramatically increases the bulk and weight of synthetic sleeping bags.


The benefits of a goose down sleeping bag, however, aren’t free. A quality goose down insulated sleeping bag is much more expensive than a quality synthetic insulation sleeping bag. The reason for the price difference should be obvious—obtaining the down insulation from waterfowl isn’t exactly a cheap or even easy process.


Storing a sleeping bag is simple, right? Just keep it in the stuff sack and toss it in the closet.

Sadly, doing this is a recipe for destroying a goose down sleeping bag. Unlike synthetic sleeping bags, which can be stored this way without kill it, a goose down sleeping bag requires some special storage considerations.

The Western Mountaineering Alpinlite Sleeping Bag is perhaps the finest goose down sleeping bag available. But if you store it inside its stuff sack you’ll still manage to kill it. More Western Mountaineering Bags at Campsaver

The problem with storing any sleeping bag in its stuff sack—but especially a goose down sleeping bag—is that long term storage in a stuff sack compresses the insulation.

Or to phrase another way, the imprisonment of a goose down sleeping bag inside a stuff sack for long periods of time reduces the sleeping bags loft.  And once a sleeping bag starts to lose loft, it loses insulating ability. This is why older, goose down sleeping bags stored in a stuff sack for years aren’t nearly as warm as they once were—as many campers have discovered the hard way after shivering through the night.

To avoid this problem, all manufacturers of goose down sleeping bags recommend storing the bags in a larger bag, such as a large garbage bag that is not sealed airtight. By storing the sleeping bag “loosely” instead of “tightly,” you prevent the insulation from compressing and thus prevent the bag from losing loft.

By contrast, synthetic sleeping bags—while they aren’t happy about being stored in a stuff sack for long periods of time—can survive it without much damage. And even just storing the bag “partially outside” the stuff sack goes a long ways towards preventing damage to a synthetic sleeping bag.


When it comes to cleaning, the winner is quite clear when it comes to sleeping bag insulation. Synthetic sleeping bag insulation is far, far simpler to clean than a sleeping bag that uses goose down insulation.

Most synthetic sleeping bags are cleaned simply by tossing them into a large, commercial sized front load washing machine—or the types often found at laundry mats. Avoid using bleach and other powerful cleaning solvents and wash in cold water. To dry, toss the sleeping bag in a large, front-load dryer and you’re done.

By contrast, cleaning a goose down insulated sleeping bag is difficult at best. Most goose down sleeping bags can’t be cleaned in a washing machine, as doing so harms the oil of the goose down—which reduces the goose downs loft and thus its insulating ability.

Moreover, when goose down sleeping bag is washed in a front load washing machine, the insulation often tends to “clump together.” Undoing these clumps is no easy task, and sometimes can’t be done at all.

For these two reasons, all manufacturers of goose down sleeping bags suggest either gently washing the exterior of the sleeping bag by hand (not dunking it into a pool) and then letting the bag air dry; or taking the sleeping bag to have dry cleaned.

Important note: If you have a sleeping bag dry cleaned, the dry cleaners must use a special process to avoid damaging the insulating. Normal dry cleaning can completely destroy the protective oils found on the goose down insulation.

What Happens to the Insulation When Wet?

One of the biggest pitfalls of goose down sleeping bags is that they are more than useless when wet. A wet (and by that, I mean soaked) goose down sleeping bag retains zero insulating ability. And since they aren’t meant to be tossed in a dryer, it can take days to fully dry a waterlogged goose down sleeping bag.

Recognizing this weakness, manufacturers now line their better quality goose down sleeping bags with water resistant, and sometimes waterproof, breathable liners such as gore-tex. These liners greatly help prvent a sleeping bag from becoming useless due to a leaky tent or accidental drop into a puddle of water.

Finally, most serious backpackers or float campers who want a goose down sleeping bag due to their weight and packability, usually buy a waterproof stuff sack and store their sleeping bags inside them. This way, should the tent leak or the pack fall into water, the sleeping bag itself remains 100% dry.

By contrast, synthetic sleeping bag insulation doesn’t lose all insulating ability when wet. A water logged synthetic bag can have some “emergency surgery” done it on trail side by squeezing out as much water as possible, then letting it dry in the sun or breeze. Moreover, once the bulk of the moisture is squeezed out from the bag, you can sleep in the bag—and the process of sleeping inside the bag actually helps to dry the insulation out. Will you get it perfectly dry? Nope, it will still be somewhat soggy—but it won’t be useless like wet goose down insulation is.

Once back in civilization, the sleeping bag can then be fully dried out by tossing it into a dryer.

The Different Types of Synthetic Insulation

There are several major types of sleeping bag insulation a consumer will stumble across when searching for a synthetic sleeping bag. While other insulation types do exist, these are the most common.

PolarGuard/Polarguard 3D/PolarGuard Delta

Polarguard, and all its various derivatives, is considered the “premiere” synthetic insulation and is what’s used in most high-quality synthetic sleeping bags. There are several varieties of PolarGuard available.

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. To clean, simply wash in cold water in a front-load washer and then tumble dry 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 lightweight) 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 and also are quite heavy and 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.

What Type of Sleeping Bag Insulation to Get and Why

Deciding which type of sleeping bag insulation to get boils down to two things: your budget and what you plan to use the sleeping bag for.

Four Season Bags for Winter Camping

Easy answer. Get a goose down bag. The risk of getting the bag wet is very low. And the less weight and bulk provided by a goose down insulated sleeping bag is worth all the money you’ll spend to buy these expensive sleeping bags.

Serious Backpacking

By serious backpacking, I mean “serious backpacking.” Basically, if you plan to be out on the trail for weeks at a time, such as walking all or part of the Appalachian Trail or Pacific Crest Trail, the answer to which sleeping bag to get is very obvious. You get a goose down insulated sleeping bag, end of story.

Western Mountaineering Sleeping Bags are specifically designed for hard core, long distance backpacking. See more at Campsaver.

And the reason for this is simple. On long hikes, every ounce and cubic inch of space matters. While care must be given to prevent the sleeping bag from getting wet, by using a waterproof stuff sack, in combination with a good tent, most “water problems” that happen with sleeping bags should be avoided.

The drawback, of course, to purchasing a goose down sleeping bag for serious hiking is that they are frightfully expensive. Top-quality goose down sleeping bags, or those bags which are ultra-light, pack down into the tiny containers and are durable enough to last for 6-months of hard use cost significantly more than more “normal” goose down sleeping bag and easily two or three times more than a good quality synthetic sleeping bag.

But if you’re hiking 100’s or 1000’s of miles, where every ounce and cubic inch matters, you spend what you need to spend and don’t complain. You’ll be happy you did in the long run.

For serious backpacking, give strong consideration to the goose down sleeping bags by Western Mountaineering. They are one of the few manufacturers that make sleeping bags specifically designed for long-distance backpacking.

View all Western Mountaineering Sleeping Bags at Campsaver

Primarily Car Camping with Occasional Backpacking

For less determined backpackers, or those who plan to spend more time “car camping” than “backpacking,” then there’s no need for an expensive ultra-light goose down sleeping bag meant to survive the rigors of the Appalachian Trail. Instead, more “normal” goose down sleeping bags or a high-quality synthetic sleeping bag works just fine.

Yes, they’ll be a bit heavier and bulkier when you backpack, but if you only go out a few days a year, those extra ounces aren’t a killer. Good quality goose down sleeping bags that work just fine for modest backpacking uses run for $250 to $300. And a good quality synthetic sleeping bag that works fine for light backpacking use and all car camping use goes for less than $200.

Manufacturers of quality synthetic sleeping bags include : Big Agnes, The North Face, Marmot and REI, to name just a few.

Two retailers that have a huge selection of quality sleeping bags are Campsaver and REI. Between these two online retailers, you’ll have no shortage of quality goose down or synthetic bags to choose from.

Float/Kayak Camping

If you’re going to be spending lots of time on the water, the probability of having a wet sleeping bag jumps dramatically. Yes, you can store the bag in a waterproof stuff sack. But still…what happens if the worse comes to worse?

For float camping, unless you also want the sleeping bag to pull “double duty” as a bag for backpacking, I strongly suggest going with a synthetic sleeping bag. Doing so saves some money that you can then spend on some quality dry sacks/dry bags to protect your sleeping bag and other gear.

Once again, two great places to look for quality synthetic sleeping bags is at REI and Campsaver.

Don’t Screw Around if You Go With Goose Down

When you buy a goose down insulated sleeping bag, you are buying premium sleeping bag insulation. The sleeping bag packs down small and is lightweight.

For this reason, it makes no sense at all to then buy a sleeping bag that is cheaply made. Cheap goose down sleeping bags have a nasty habit of either ripping at the seams or, more commonly, “leaking” insulation. Finally, cheaply made goose down sleeping bags “give up the benefit” goose down provides, by being heavier and bulkier than a quality goose down sleeping bag is.

The moral of the story is this—if you spend the money on a goose down sleeping bag make sure the rest of the bag is just as high quality as the insulation is. Over the longer term, the extra money is well spent.

And in the world of goose down sleeping bags, the bags made by Western Mountaineering are regarded as the best. They are the durable, pack down into a small container and either a waterproof or water resistant shell. If you’re serious about getting a goose down insulated sleeping bag, might as well get the best there is.

View all Western Mountaineering Sleeping Bags at Campsaver