Insulation is important for your winter gear, but as with everything in gear considerations, there’s a balance you have to look for. You want something that’s effective, comfortable, and not so heavy or bulky that you can’t move around easily.
There are several insulation options to choose from on the market. Two of these are PrimaLoft, a synthetic insulating material, and down, which comes from birds.
Before we talk about insulation types, it’s important to understand why both PrimaLoft and down make good insulation. This type of insulation doesn’t rely on weight or material thickness. Instead, it’s lightweight and breathable because of how it traps air.
Both PrimaLoft and down make good insulation because of their fill power, or loft. In insulation, the more loft a material has, the better it is at insulating.
When you’re shopping for gear with down insulation, you may see a loft number or fill number on the label. This number represents the number of cubic inches filled by an ounce of down. This is directly related to the size of the down cluster. Large down clusters occupy more space than smaller down clusters, even though they might weigh the same. But bigger down clusters trap more air between them, and that trapped air is what gives down its insulating ability.
Down’s cluster size is determined by the environment that the birds it comes from live in. Birds raised in cold environments have bigger down clusters than birds raised in warm environments. With synthetic materials like PrimaLoft, fiber cluster size is determined by the manufacturer, so it’s more uniform across products. Both PrimaLoft and natural down have high loft, so they are great insulators.
Staple length is another element of garment and gear insulation that’s important to understand. Staple length refers to the length of the fiber that’s used for insulation. Down always has a short staple length because it’s made of short feathers. But synthetic insulation can be either short-staple or continuous filament. Knowing the difference is an important distinction.
Short-staple insulation mimics down. It uses short strands of fine filaments that are packed densely to maximize heat retention. Sleeping bags, jackets, and other items with short-staple insulation are soft and flexible and easily compressed— just like down-filled gear. This type of insulation isn’t the most durable, and it can move around to create cold spots. However, the flexibility and easy packing ability of these products make them very popular.
Continuous-filament insulation uses long, thick filaments that are stronger and more durable than short-staple filaments. Gear with this type of insulation has a stiffer feel and is less easy to pack than short-staple gear. However, the longer filaments stay in place much better and are less prone to creating cold spots.
All of the PrimaLoft insulation types are short-staple. The PrimaLoft company does not manufacture continuous-filament insulation. This is because it’s meant to mimic down. However, when you’re shopping for gear, you may come across continuous-filament insulation, and we think it’s important to understand the different terms that come up when you’re hunting for that perfect jacket or sleeping bag.
What Is PrimaLoft?
Primaloft is a synthetic microfiber insulating material that was developed in the 1980s for the United States Army. It was originally meant to be used in sleeping bags and was designed to meet the insulating standard of down when dry, but outperform down when wet.
PrimaLoft’s story began in 1983 when the US Army commissioned its development. After only three years of development, the patent for “Synthetic Down” was granted in 1986. By 1989, the product had reached the consumer market, when LL Bean used it in jackets. The outdoor market was eager to embrace a down alternative, and demand for PrimaLoft skyrocketed. By 1992 the insulating material was used in products such as gloves, sleeping bags, and outerwear. Since then, PrimaLoft can now be found in all types of outerwear, footwear, and any other cold-weather gear you can imagine.
PrimaLoft works due to the mix of fiber sizes trapping air. In every cubic inch of PrimaLoft insulation, thousands of tiny air pockets are formed by the overlapping fibers. PrimaLoft makes three grades of insulation: Gold, Silver, and Black. PrimaLoft Gold is comparable to down with a loft number of 500-550. Silver is slightly less effective, and Black is the least insulating. You’ll often find PrimaLoft Black in lightweight fall jackets, while PrimaLoft Gold is what you’ll find in highly-rated winter sleeping bags, for example.
What Is Down?
Down is the layer of fine, fluffy feathers found under the tougher exterior feather layers. Down feathers have a short shaft (also called the rachis) and don’t have the interconnecting barbules that connect the fibers of exterior feathers. Down is extremely soft and traps air next to a bird’s skin, which helps keep the bird warm and improves the buoyancy of waterbirds.
Down serves many natural purposes for birds, including warmth, nesting material, and buoyancy. Humans also use down for many purposes, and one of the most important of these is insulation. People have been using down as insulation for a very long time. While historically we know that the down of various ducks, geese, sea birds, and other waterfowl has been used as insulation, most of today’s down comes from domestic geese. The most expensive kind of down, eiderdown, is collected from the nests of wild eider ducks. But the down that’s used in the majority of insulation actually comes from the meat industry as a byproduct of the production of goose meat.
Today, you can find down in duvets, sleeping bags, and outerwear. It’s a very common type of insulation because of how lightweight and effective it is.
Advantages of PrimaLoft
PrimaLoft’s biggest advantage is its performance when wet. Because it’s made of polyester, it is highly water-resistant. And if it does get wet, the material doesn’t absorb the water and retains its insulating ability. When down gets wet, it clumps together and stays that way unless you immediately break it up— but you never have to do that with PrimaLoft.
Another advantage of PrimaLoft is that it’s hypoallergenic. As a natural material, down triggers some peoples’ allergies and causes reactions including blisters inside of the nose. While few people have genuine feather allergies, the mites that live on feathers can cause a painful reaction. So if you’ve got animal allergies, you might want to avoid down insulation.
PrimaLoft can also be easily washed at home, or dry cleaned if necessary. Because polyester doesn’t clump, you can put your PrimaLoft gear in the washing machine and tumble dry it with no or low heat to return it to its original condition.
Finally, PrimaLoft doesn’t rely on animal agriculture— and while it is a synthetic material, it can still be an eco-friendly choice. There are a couple of variations that have a smaller environmental impact than the original. One of these, PrimaLoft Eco, uses 70% recycled materials. The other, PrimaLoft Bio, uses 100% recycled biodegradable fibers that completely break down in 394 days in landfill conditions.
Both PrimaLoft Eco and PrimaLoft Bio meet the original PrimaLoft performance standards, so you don’t have to sacrifice performance for environmental friendliness. PrimaLoft is introducing more recycled material to their other products, like the now 100% recycled ThermoPlume; eco-consciousness is a cornerstone of the company’s goals.
Advantages of Down
Down’s biggest advantage is that there’s nothing warmer or more lightweight than these tiny, soft feathers. The highest-rated synthetic insulation is comparable to 500-550 loft down… but you can find down that’s rated at 900 loft.
Down is extremely lightweight and traps a lot of air, which means that it can be crushed down to very small sizes. This makes down-filled gear easy to pack— when folded, it doesn’t take up much space. When you unpack your gear and fluff it up a bit, the feathers will spring back to their original shape and the air will return.
Down is also durable. When properly cared for, a down jacket will last much longer than a jacket with synthetic insulation. Washing a down jacket does take special detergent and extra steps, but choosing down does mean that you will ultimately save money in the long run.
Down is an eco-friendly material, too. Down and feathers have the lowest carbon footprint of any material, and modern down is largely a byproduct of another industry. The vast majority of the down used in today’s cold-weather gear comes from meat birds and is considered a waste product from the poultry farming industry. Down can also last for 20 to 30 years as an insulating material, so it’s relatively easy to find high-quality secondhand down jackets, sleeping bags, and other gear that will still provide the insulation you need for your adventures.
PrimaLoft Vs. Down
In many ways, down and PrimaLoft are virtually equivalent. Here, we’ve put the two head-to-head to see how they compare in different areas.
Both down and PrimaLoft are great insulators. However, down has a better weight-to-insulating ability ratio. For the gear that most people need, there isn’t much of a difference; however, at the highest levels of performance demands, down will outperform synthetic insulation unless down gets wet.
Synthetic insulation like PrimaLoft is almost always cheaper than down. This is especially true of eiderdown, which is extremely expensive. A simple eiderdown duvet can cost over $5000! But most down isn’t eiderdown, and goose down garments are usually quite reasonably priced.
Natural down is much more durable than PrimaLoft. Every time PrimaLoft is flattened (for example, when you’re packing it), it loses some of its insulating ability and doesn’t get it back. Down’s fluffiness springs back after it’s been crushed, so it doesn’t lose that insulating ability. Properly cared for, a down jacket can last for decades.
You might think that because down comes from water birds, it’s highly water-resistant. However, this could not be further from the truth. Down doesn’t need to be water-resistant to keep water birds warm. First, the exterior feathers of these birds are water-resistant due to the structure of the feathers’ filaments and the way they hook together.
Secondly, these feathers create a tight layer that creates a physical barrier between the down and the water. And finally, nearly all water birds produce waterproofing oils that they spread on their feathers when they preen. All of this means that the down of waterbirds virtually never touches water.
Because down has such a soft structure, it has absolutely no water resistance. The minute down gets wet, it clumps and loses all of its insulating ability. If down gets wet, you have to manually break up the clumps as it dries. You can do this pretty easily in the safety of your laundry room, but if you’re out in the field, your down-filled gear can become a liability if it gets wet. This is why a lot of modern down-filled gear is made with waterproof outer materials. If you’re going to be hiking in an area where there’s heavy rainfall or other wet conditions, make sure that your down-filled gear’s water resistance is still performing well.
PrimaLoft, on the other hand, was designed to outperform down when wet. Water rolls right off the polyester fibers and is wicked away to the outer layer, meaning that your PrimaLoft-filled gear will keep you warm even if water gets into the insulation. When it comes to wet weather conditions, there’s no comparing the two— PrimaLoft outperforms down every time.
PrimaLoft and down are both equally breathable— and the breathability level of either one of them is good. The actual breathability of your cold-weather gear really comes down to the outer materials used in the garment, not the insulation itself.
Finding Down Vs. PrimaLoft Gear
Sleeping bags, gloves, jackets, boots, and other gear will often say if it utilizes down or synthetic down. Due to the fact that PrimaLoft is a well known synthetic down manufacturer, you will often find that PrimaLoft is highlighted in the marketing of that product.
The Final Word
Ultimately, both down and PrimaLoft are great insulators with lots of good qualities. The primary safety concern is the likelihood of your insulation getting wet— which can be prevented in either case with a water-resistant or waterproof outer material. But when it comes to performance, both down and PrimaLoft are excellent materials, and you should feel confident that either one will is a great material for different needs.
Max DesMarais is the founder of hikingandfishing.com. He has a passion for the outdoors and making outdoor education and adventure more accessible. Max is a published author for various outdoor adventure, travel, and marketing websites. He is an experienced hiker, backpacker, fly fisherman, trail runner, and spends his free time in the outdoors. These adventures allow him to test gear, learn new skills, and experience new places so that he can educate others. Max grew up hiking all around New Hampshire and New England. He became obsessed with the New Hampshire mountains, and the NH 48, where he guided hikes and trail runs in the White Mountains. Since moving out west, Max has continued his frequent adventures in the mountains, always testing gear, learning skills, gaining experience, and building his endurance for outdoor sports. You can read more about his experience here: hikingandfishing/about