Skiing versus snowboarding. Mountain biking versus road biking. Tupac versus Biggie. Who hasn’t engaged in these bottomless debates? Perhaps the mother of all campfire arguments, however, is the age-old synthetic versus down sleeping bag scenario and hopefully help you get to the bottom of figuring out which bag or quilt best fits you.

backpacking with thermarest sleeping bag

Down vs. Synthetic: Price

A deciding factor for campers on a budget is the significant price difference between a down bag and a synthetic bag. With the increasing popularity of fashionable down jackets worldwide, that magical insulating undercoating that provides warmth to geese, ducks and now humans is a hot commodity. And because of the demand, down is more expensive. Traditionally, a down sleeping bag started at around $300. However, the price can vary depending on what’s happening to the supply of down globally. In 2013, for example, a bird flu outbreak wiped out a large chunk of China’s down supply, therefore bumping up the price of down sleeping bags worldwide.

It’s worth noting that in the last few years, duck down has become an available fill in many bags, and is cheaper than goose down. Low fill-power duck down bags are now available for under $200.

Bottom Line:

If money is tight and how much you spend is your main concern, a synthetic bag or a low fill-power duck down bag is your ticket to outdoor comfort.

down vs. synthetic quilts

Down vs. Synthetic: Warmth to Weight Ratio

The superiority of down’s warmth to weight ratio is unmatched. That fill-power we mentioned above … yeah that’s where down shines. So what is fill-power? Basically it’s a measurement of the cubic inches an ounce of down can fill inside a lab container. Simply put, fill-power gauges the loft or fluffiness of the down. The higher the fill-power, the warmer the bag. Synthetic insulation, which is made from polyester fibers, has a heavier warmth-to-weight ratio, which also affects a synthetic bag’s compressibility. This means that a synthetic piece with the same temperature rating as a down piece will be heavier and won’t pack down as small as a comparable down bag or quilt.

Bottom Line:

If you’re a gram shaving alpinist, a fast and light backpacker, or just a camper who values a light and compact load, a down bag or quilt is your primo choice.

Down sleeping bag Insulation
Therm-a-Rest’s eraLoft™ insulation is made of water-resistant polyester that retains warmth when wet and dries fast. The highly compressible microfibers offer excellent loft and hollow-core fibers trap heat efficiently.

Down vs. Synthetic: Water Resistance

The coup de grâce for those residing in the synthetic camp is often the topic of water resistance. And they’re right: when it comes to playing in the rain, camping in the snow or days on a river, few can argue that a synthetic sleeping bag is the safer bet. Synthetic insulation is designed to maintain its insulating qualities even when wet. Plus it dries faster. For down, moisture is its kryptonite.


However, a recent evolution of technology has added fuel to this argument. Enter hydrophobic down. Water resistant down, such as Nikwax’s Hydrophobic Down™ is created by treating its molecules with a hydrophobic chemical (water resistant coating)—virtually adding zero weight to the insulation. Nikwax Hydrophobic Down™ will be used in all of our down sleeping bags, quilts and blankets beginning in 2016. In our research, Hydrophobic Down™ is proven to absorb 70% less moisture than untreated down and dries three times faster.

When pitted against each other, however, a synthetic bag still outperforms a treated down bag in very wet conditions.

Bottom Line:

If you plan on testing the limits of your sleeping bag or quilt in wet conditions, a synthetic piece is more reliable.

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