Which is better a down or synthetic filled jacket? This is a very common question and the answer is highly dependent on what environments and conditions the jacket will be used in. In this post I will aim to direct you to the right insulated jacket for your needs.

The overriding principle at work in insulated jackets (and sleeping bags, mittens, or any other insulated apparel) is the same. Air is trapped in the small spaces between the filaments of down plumes or strands of polyester, providing warmth in cold conditions. Loftier (or puffier) materials consist of more air, and offer a greater warmth-to-weight ratio.

Types of Insulation

We are now spoilt for insulation choices, hence the confusion. Below are the main options:

Down: Nature’s best insulator—the most warmth for the least weight and bulk. Down hates water so don’t get it wet.

Water-repellent down: Down treated with a molecular-level polymer that can withstand mist or light moisture. That’s a big bonus, however you still shouldn’t let it get wet for prolonged periods.

Synthetic materials: Water-repellent, quick-drying fibers engineered to mimic down’s loft, low weight and compressibility. Down edges synthetics in all those areas, but synthetics are getting better with each new generation of products.

MerinoLOFT: Icebreaker MerinoLOFT uses a combination of merino and nylon to provide a fill that is very comparable to synthetic materials for weight and compressibility. There is a strong emphasis on the use of natural materials.

  • Lightest
  • Most compressible
  • Best warmth to weight
  • Won’t insulate when wet
  • Slow to dry
  • Expensive
  • Cold & dry conditions
Water Repellent Down
  • Same warmth to weight  & compressibility as regular down
  • Will insulate when exposed to light rain
  • Dries slightly quicker than regular down
  • Still best to keep it clear of heavy rain
  • Expensive
  • Dry or damp conditions
  • Water resistant
  • Relatively quick to dry
  • Less expensive
  • Bulkier, heavier and less breathable
  • Less durable
  • Most conditions
  • Will still keep you warm if gets damp
  • Anti-Bacterial so wont get as stinky as synthetic
  • Majority made of natural products
  • Not as quick to dry as Synthetic
  • Bulkier and heavier than down
  • Dry or Damp conditions



What is it: 

  • Natural plumage found at the undercoating of geese and ducks.
  • When clustered together, high-lofting down plumules (tufts) trap air with unparalleled efficiency.
  • An exceptional insulator, revered for being light, highly compressible and breathable. Down is relatively durable as well. If cared for properly, down plumules retain their near-original lofting ability for decades. Down’s luxurious feel adds to its popularity.

How down is graded:

  • “Fill or Loft” measures how many cubic inches 1 oz. of down can fill inside a tube after being aerated and has had time to resettle.
  • Fill or loft generally ranges from 450 to 900. In outdoor equipment, fill ratings commonly fall between 600 and 800.
  • The higher the loft the greater quality and results in a lighter product.
  • Premium down comes from very mature geese and is graded 750 to 800+ (hence its greater expense).

Down & moisture:

  • If down gets wet, it tends to collapse, clump and can no longer insulate. In addition, down is very slow to dry, often requiring a day or more. This is down’s biggest issue however most down garments will use water resistant fabrics to help counter act this problem.
  • Recently, several water-repellent treatments for down have been introduced. They involve a durable water repellent being applied to down plumules at a molecular level (kind of like the Teflon coat on a frying pan). Treated down can retain its loft if exposed light moisture. However it will still clump if hit by heavy rain or if you fall into a creek. Treated down will also dry a little quicker than untreated down.

The Down filled jackets and vests Paddy Pallin stock can be found instore or online.

pat nano air small


What is it:

  • Ultrafine fibres of polyester, formed either in short staples (5cm or less) or long, continuous filaments. In both designs, the fibres intertwine and create dense, warmth-trapping air pockets.
  • The major name in Synthetic fill is PrimaLoft®. PrimaLoft works primarily with short-staple designs. PrimaLoft Gold Series is its premium option.
  • Many outdoor brands will apply their own proprietary tweaks to an insulation. One example is ThermoBallTM from The North Face. TNF shaped PrimaLoft insulation into tiny puffballs and packs them densely into apparel baffles. The goal is to replicate down’s loft, weight and compressibility.

How synthetics are graded:

  • There is no recognised outdoor industry standard on grading synthetic fills, which can cause some confusion when comparing different styles.
  • However PrimaLoft estimates its insulation products offer the equivalent of 500 to 550 fill-power down. The North Face calculates that ThermoBall offers the thermal efficiency of 600 down.

Synthetics & moisture:

  • Synthetic fibres are far more resistant to moisture than down. Even when soaked, wet synthetics can provide more insulation than wet down, however its only incrementally greater.
  • Synthetic fibres dry faster than down. Sun, moving air, even body heat can help them dry out within a day, possibly within hours.
  • Insulation has a better chance of staying dry if the durable water repellent (DWR) on the shell of your jacket is in good shape.

To see the Synthetic Insulation options for men and women head instore or online.

Who’s the winner??

Can we declare a winner in the down vs. synthetic debate? Like many things in life, one is not strictly better than the other in all circumstances. Twenty years ago, down was clearly the better overall option. As technology has improved, however, synthetic has made significant headway. In order to find your best match, keep these points in mind:

Down is the best option if low weight and compressibility are your priorities. You travel in cold, dry conditions or protect your jacket from moisture using a waterproof shell and you are willing to pay a bit more up front under the knowledge that the insulation will be more durable.

If you want a want a warm jacket and don’t mind just a little extra bulk and weight, prefer not to stress about water’s impact on its insulation, and want to save a some dollars, then a synthetic fill will be best.

About The Author

Dave Casey

Dave has worked as an International Expedition Leader and in Outdoor Education for over 15 years. He has extensive travel and guiding experience in Australia, NZ, Asia, South/North America and Europe. In his spare time Dave is a keen bushwalker, mountain biker and climber while also dabbling in some mountaineering and sea kayaking. He is currently working at Paddys as the National Account Manager, to fund all of the above.

3 Responses

  1. Jamie Mackenzie

    I would have thought that the biggest deciding factor was ethics.
    Merino and down industries both have questionable sourcing and animal welfare issues.

    • Dave

      Hi Jamie

      The environmental ethics is a great point and something that Paddy Pallin takes great interest in and takes very seriously with the brands we stock.

      In regards to our Down Patagonia leads the industry in relation to ethical treatment of the Geese. The North Face and Marmot are closely following. All of these brands have a policy that requires suppliers to send audit reports indicating no live-plucking or force-feeding took place and made a committment to traceability. Patagonia also don’t accept parallel production in slaughterhouse and have measures taken to avoid mixing when washing. Head to the Four Paws website for more info http://down.four-paws.org/en/?locale=en_US

      Icebreaker also works very closely with its merino providers in regards to ethical treatment of their Merino. Icebreaker is mulesing free and has a number of other standards set. The Icebreaker website has some more information in regards to the ethical treatment of their Merino. https://eu.icebreaker.com/en/icebreaker-ethics/how-we-treat-animals.html

      We currently have another post being written by Lachlan that goes over the ethical care of animals in greater depth. With it planned to be posted in a couple of weeks.

      Thanks again for taking the time to comment and please let me know if you have any other questions.


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