Is it to-may-to or to-mah-to? The chicken or the egg? Barry Bonds or Hank Aaron?
Life is full of conundrums that have the potential for sparking intense debate. Outdoor enthusiasts can get pretty "hot" over the subject of keeping warm (if you'll please pardon the very bad pun), with purists insisting on the superiority of down and technology-embracing adventurers touting the benefits of synthetics.
While we may not have a definitive winner, each type of insulation does have its place in the great outdoors. We've created this guide to help you choose the insulation option that will work best for you. Looking for a jacket to wear around town or a warm sleeping bag for a winter camping expedition? We've broken down the advantages (and drawbacks) of both down and synthetics so you can make an educated purchase.
Contrary to popular belief, down insulation is not made of feathers. Instead, down is actually the fluffy undercoating of a bird's plumage (geese, ducks, and other waterfowl) and looks like interlocking wisps of dandelion fluff. Down works for you just like it works for the bird; it keeps you warm by trapping an abundance of body heat within its tiny clusters. And because it is also breathable, down allows unwanted moisture to escape.
Quick Guide to Down
- Is warmer than synthetic insulation ounce for ounce. No manmade fiber matches down in its warmth-to-weight ratio.
- Retains its shape and loft and, with proper care, can last a lifetime. No synthetic can beat down's longevity. Down holds up better over years of use.
- Wicks body moisture and allows it to evaporate. Moisture wicking goes a long way in keeping you comfortable.
- Is highly compressible and lightweight. Although synthetic insulation has come a long way, it doesn't hold a candle to down's ultralight weight and amazing compressibility. Down is the preferred choice for backpackers who want to travel light in dry conditions.
- Loses its insulating properties when wet and is slow to dry. And if down gear is damp-especially in a humid climate-it will take a great deal of time to dry. Don't count on leaving your wet sleeping bag to dry while you take a day hike. Chances are it may not be dry enough for you to sleep in that night.
- Requires special cleaning. Cleaning down gear is labor intensive. Harsh detergents and chemicals will break down its natural loft and luster. If you don't dry clean your gear, only very mild detergents or down-specific cleaning products should be used.
- May contain allergens. Down is not entirely hypoallergenic. While the down may not cause an allergic reaction itself, lower quality down can harbor dust particles, debris, or other non-down materials, causing a reaction. However, higher quality down is cleaned according to strict industry standards. If you're prone to allergies, it's wise to invest in better quality down products.
- Costs a pretty penny. Down insulation is far more expensive than synthetic insulation, but it's a great value for the avid outdoor enthusiast if you factor in down's resistance to deterioration. Recreational campers and hikers can get the job done with synthetic gear, which is usually a more wallet-friendly option.
Types of Down
Down-filled sleeping bags and outerwear are generally warmer and lighter than their synthetic counterparts. Down is considered the best insulation for cold, dry weather conditions and expedition use and comes in the following varieties:
- High loft goose down is made from very fine down and provides the best insulation of any other filling because it traps the most air. High loft down is mostly used in expedition sleeping bags and outerwear where minimal bulk and low weight are critical.
- Goose down is very fine and more reasonably priced than high loft down.
- Duck down is less fine than goose down and considerably less expensive.
Facts about Fill Power
- Down is rated according to fill power-meaning the number of cubic inches one ounce of down will occupy. For example, if one ounce of down takes up a volume of 650 cubic inches, it is given a 650 fill power rating.
- Loft refers to the thickness of the insulating material in a sleeping bag or garment.
- The quality of the down is directly related to its fill power rating. Thus, down warmth is a function of both fill power and the amount of fill in a sleeping bag or garment.
- High quality down has a high fill power and is much loftier than down of a lower quality, requiring fewer ounces of down to create insulating warmth.
- Most companies use only goose down which has a minimum fill power of 500 to 550.
- The higher the fill power, the better the down will insulate because there is less of a chance of "cold spots"-areas in the bag or garment where there is no down.
- Today's higher-end manufacturers offer 600 to 750 fill power as their standard fill.
- If a label doesn't specify fill power, it is usually because the down falls in a range below 400 cubic inches or the item contains less than 75% down.
Making the Grade
Down also comes in a number of different grades (or qualities). For example, a 90% goose down garment will consist of 90% down and 10% feathers. The higher the percentage is, the purer the down will be. High percentage grade insulation will also be very low in weight and bulk, but higher in price.
The Bottom Line
Down is Mother Nature's best insulator. It provides incredible warmth for minimal weight and is highly compressible and resilient; but it comes at a price.
Many of us can probably remember a hiking trip we took with our family as a child. We all wanted to be wrapped in the heavenly warmth of down, but it was out of Dad's price range. Instead we layered. We layered until we could not bend our arms or legs. And then we whined.
Luckily, synthetic technology has gotten a lot more sophisticated and now there are numerous manmade materials that mimic down without the hefty price tag.
Synthetic insulation is essentially polyester threading that is molded into long single threads or short staples to mimic lofty down clusters. Thinner and lighter threads fill voids and trap warm air more effectively, while thicker strands sustain the loft and durability.
Quick Guide to Synthetics
- Is water resistant and provides insulation when wet. Synthetic fills are, at the very least, resistant to moisture while many will actually shed water rather than absorb it. These water-resisting properties allow the synthetic fill to retain the majority of its insulating properties when wet.
- Dries quickly. When a synthetic fill does get wet, the moisture is trapped in the air pockets between the fibers rather than in the fibers themselves. For this reason, synthetic fills will dry much faster than down fills-usually in a matter of minutes in direct sunlight.
- Is generally less expensive than down. Unless geese start lowering prices on down, synthetic insulation will always be cheaper than its natural counterpart.
- Is easy to care for. Most synthetic fill sleeping bags or garments are machine washable and dryable.
- Is completely hypoallergenic. Because synthetics are manmade, they are, for the most part, hypoallergenic.
- Offers a greater range of options for those on a budget. Synthetic fills vary greatly in durability, bulk, weight, and price so there are more options available for beginning hikers or children who quickly outgrow their clothes.
- Can be bulky and less compact than down. Synthetics tend to be much bulkier and less compact than down, taking up valuable space when you're trekking around.
- Heavier than down. Synthetic fill requires more weight to get the same warmth that the lighter down provides.
- Breaks down over time. Synthetic fibers gradually break down no matter how well you care them. You may find yourself replacing synthetic products quicker than you would down products.
- May cause fit problems. Some less-expensive synthetic fills can be stiffer than down and may not drape as well. Higher-end synthetic fills, though, can be hard to distinguish from down and fit just as well.
Common Synthetic Fill Fibers
With rapidly advancing technology, new synthetic fill materials are being created all the time. Here is a list of some of the most popular synthetic insulations.
- Polarguard® is an insulating material made of continuous synthetic fibers. It retains its loft and insulating properties when wet. It is also non-allergenic, mildew-resistant, and machine washable/dryable.
- Polarguard® 3D maintains the same properties as its predecessor, but is made of a softer fiber that more closely resembles down.
- Polarguard® HV, like the original and 3D versions, is made of continuous synthetic fibers, but is 25% lighter and more compressible making it an ideal material for use in backpacking and expedition gear.
- Polarguard® Delta is the latest development in synthetic insulation. Constructed of hollow core continuous filaments, this insulation is lighter, more durable, and more thermally efficient than any other Polarguard® product. These advances are achieved by a larger diameter fiber with more hollow space inside to create a stronger, higher lofting insulation. Polarguard® Delta is a good fill for items like sleeping bags which are subject to repeat stuffing.
- Primaloft® is an ultra-fine microfiber blend that is incredibly soft, lightweight, and water repellent. It also has a down-like softness that adds comfort and appeal. In addition to sleeping bags and outerwear, Primaloft® is used in the construction of insulated footwear.
- Primaloft® One has the highest warmth-to-weight ratio of any synthetic insulation currently on the market. It is soft and durable, high loft, 100% polyester microfiber insulation. It is thermally efficient, lightweight and compressible, fast drying, and water resistant. However, it is also the most expensive synthetic to manufacture.
- Thinsulate® was introduced as the original "warmth without bulk" synthetic insulation. It retains its ability to insulate even when wet. The ultra-fine microfibers trap warm air more efficiently than larger fibers and in doing so reflect back more of the body's radiant heat. It's breathable and moisture-resistant.
- Thinsulate® insulation comes in 40, 70, 100, and 150 gram weights. The higher the gram weights, the warmer the insulation will be. Thinner insulation is used in the construction of casual sportswear and high activity winter sportswear, while the thicker insulation is used in the construction of extreme weather clothing. Headwear, gloves, and shoes are made of insulation of various thicknesses.
All Thermolite® insulations are designed for exceptional warmth-even when wet-without the bulk of down. They are also machine washable and dryable.
- Thermolite® Extreme is a high-tech insulation engineered to provide the most warmth per weight and durability of any Thermolite® performance fill. It is also compactible and possesses a supple drape.
- Thermolite® Extra most closely resembles the warmth, softness, and fullness of down. It provides a high loft that retains its fullness and remains resilient through many uses.
- Thermolite® Micro is less bulky than Thermolite® Extra, but provides comparable softness and warmth. This lightweight insulation provides warmth when wet and dries quickly. It is also the most compatictible of all the Thermolite® insulations.
- Thermolite® Plus is designed for use in extreme conditions. It provides the most warmth of any Thermolite® insulation when wet. It also holds up exceptionally well after multiple washings.
- Thermolite® Active is to be used during high-energy pursuits. It provides warmth at a minimum thickness and wicks moisture away from the body much better than down and the other Thermolite® insulations.
Other Synthetic Materials
You will see a variety of synthetic materials under various names on the market. These synthetic insulation materials have similar properties and characteristics. Here are a few names you may encounter:
- Dryloft®: A two-ply laminated shell fabric designed specifically for insulating parkas and sleeping bags. Dryloft® is twice as breathable as Gore-Tex®, but not as waterproof.
- Hollofil®: A polyester insulation used in bargain brand sleeping bags and apparel.
- Liteloft®: A polyester/olefin used in sleeping bags and outerwear.
- MicroLoft®: A polyester insulation made of fibers thinner than a human hair. The dense structure is said to trap heat more efficiently than other synthetics of equal thickness. It is also highly water resistant.
- Quallofil®: High-loft polyester insulation with a soft, down-like feel. It is used primarily in sleeping bags, but also in insulating outerwear and accessories.
- Thermoloft®: Medium-loft synthetic insulation that combines solid-core polyester fibers with hollow Quallofil® fibers. The blend is used most often in insulated outerwear, where high-loft fills are too bulky and low-loft fills aren't warm enough.
Many outerwear and sleeping bag manufacturers have their own registered brands of synthetic insulation. Look for:
- ThermaWeb® from Spyder
- MarmaLoft® from Marmot
Can we declare a winner in the down vs. synthetic debate? The fact of the matter is that down is better except when synthetic is better. The distinguishing line gets more blurred every year. Just a few years ago, down was unmatched; but today's lighter, warmer, and more compressible synthetics are slowly closing the gap. In order to find your best match, keep these key things in mind:
- Down works well for just about everyone-unless you frequently find yourself in wet weather.
- Synthetic insulation is a good choice for children and for newbie campers or backpackers because of its lower cost and quick-drying properties.
- Down still wins in terms of weight, compressibility, and durability, but synthetic is the hands-down winner in the cost department.
- Continuous technological advancements in synthetic materials are giving down a run for its money. You may not be able to tell the difference.