Click here if you want to jump straight to my list of the warmest garments available.

I’ve been researching the warmest wool products available. Here’s what I discovered:

Qiviut (Musk Ox Down)

Qiviut (pronounced “kiv-ee-ute”) is the name for the downy hair of the musk ox. It is the warmest fiber in the world — about eight times as warm as sheep’s wool. It’s also an ultralight fiber. So it’s an extremely warm, very light and very soft fiber.

It’s also quite expensive — a pair of Qiviut socks will costs about $175.

Musk oxen live in Alaska and Canada where temperatures sometimes drop to –100ºF (-73ºC), so they need protection.

I’ve been testing Qiviut scarfs — and they are superlatively warm. Qiviut’s combination of intense warmth and ultralight hand is unique.

A single garment of it can make a significant difference on a frostbitten night.

In Alaska, qiviut is obtained from farmed animals or gathered from the wild during the molt. Unlike sheep, the musk ox are not sheared.

Many of these Qiviut websites are run by the knitters themselves:

• 100% Qiviut Socks — 100% qiviut (musk ox) — $175
• 35% Qiviut Blend Socks – 35% Qiviut, 40% Merino, 15% Bamboo, 10% Nylon – $94
  
• 100% Qiviut Harpoon Cap – $180
• 100% Qiviut Heavy Weight Aleutian Scarf – $260
• 100% Qiviut Handwoven Scarf – $250
• 100% Qiviut Knitted Blankets – from $2,000 to $10,000
• 100% Qiviut Blankets – from $800 to $2,100

Yak Down

Similar to qiviut, yak down is a very warm fiber that’s also lightweight and soft. It’s a slightly more affordable alternative to the rare qiviut.

Yaks are primarily raised by nomadic Tibetan and Mongolian families. Their wool is combed once per year in the springtime.

According to Kora, a yak performance wear company, yak fabric is 40% warmer merino wool. It has 66% greater air permeability and 17% greater water vapor permeability (tested with ASTM D1518, ASTM D737, ASTM E96).

Bison Down

Bison down is a very warm, insulating fibre. It is also very durable for such a soft fibre. It has a moisture regain of about 30%, compared to 18% for wool — this means that even when saturated, the fibre draws moisture away from one’s skin.

There is only a limited amount of fibre available – estimated at 10,000 pounds per year versus 2,100,000,000 pounds of sheep wool.

It is harvested in Colorado and South Dakota, as a by-product of the bison meat industry.

• Bison and Yak Blend Socks – 40% Bison, 40% Yak, 10% Silicone  – $40
• 45% Bison Down Fox River – 45% Bison, 20% Silk, 20% Cashmere, 15% Tencel – $40 – this is an excellent sock — however it degraded after a year
• 90% Bison Down Queen Size Blanket – 90% Bison Down and 10% Acrylic – $3,500
• 90% Bison Down Gloves – 90% Bison Down, 10% Nylon – $75

Alpaca Wool

Alpaca wool is about three times as warm as sheep’s wool. It is fine, lightweight and lustrous.

Alpaca is soft as cashmere but stronger and less costly. It’s more durable than merino.

It is durable, and bears no lanolin, which makes it hypoallergenic.

Alpacas are kept in herds that graze on the level heights of the Andes of southern Peru, northern Bolivia, Ecuador, and northern Chile.

• 74% Alpaca Extreme Sock – 74% Alpaca, 24% Nylon, 2% Elastic  – $28
• Alpaca Warrior Blend Sock – these socks are warm and inexpensive — degrades fairly quickly though – $12.75

Other Wools

Other warm (and very soft) wools include angora, cashmere, vicuna and guanaco.

Durability and Fineness

In terms of durability, bison is in most cases the strongest, followed by qiviut and yak down, followed by alpaca and then merino.

In terms of fineness, any fibre that has a diameter of 20 µ (microns) or less will feel very soft to the touch. In the alpaca world, the labelled “royal” alpaca should indicate fibres under 19 µ, “baby” alpaca should indicate fibres that are around 22.5µ and “superfine” alpaca is 26µ. There’s also an International Alpaca Mark that indicates the fibre is less than 28 µ. In the merino world, look for wool labelled “ultrafine” (around 15-17 µ) or “superfine” (about 24 µ).

Here’s a list of fibres from finest to coarsest (in microns): Suri Alpaca (10 -15 µ), Qiviut (11-13 µ), Yak (15 – 19 µ), Huacava Alpaca (15 – 29 µ), Cashmere (15 – 18.5 µ), Ultrafine Merino (17 µ), Yak Down (17.5 to 19µ), Bison (18.5 µ), Superfine Merino (24 µ), Standard Wool (30 – 32 µ), Human Hair (60 – 80 µ).

Based on this criteria, these are the warmest woolens I could find:

Warmest Socks

•  100% Qiviut Socks — 100% qiviut (musk ox) — $175  (not currently available)
  
• 35% Qiviut Blend Socks  — 35% Qiviut, 40% Merino, 15% Bamboo, 10% Nylon – $94
  
• Khunu Yak Wool Boot Sock — a very warm casual sock — 85% yak wool and 15% nylon — £22.00 GBP
• Bison and Yak Blend Socks — 28% Bison, 28% yak, 27% nylon/14% silicon polyester/3% Lycra spandex – $55 — a very warm sock and with a good tight weave
• 45% Bison Down Fox River Socks — 45% Bison, 20% Silk, 20% Cashmere, 15% Tencel — $35 — Wonderful sock — ultralight but very warm — one of my favorite socks.
• 74% Alpaca Extreme Sock — 74% Alpaca, 24% Nylon, 2% Elastic  — $21 — a very thick but warm boot sock
• Alpaca Warrior Blend Sock — exact blend unknown — a basic warm sock  — $12.75

Warmest Gloves

• 90% Bison Down Gloves – 90% Bison Down, 10% Nylon — the bison wool makes this glove particularly warm — its styling is rough — so for outdoor sports use only  — $75
• 100% Alpaca Double Knit Gloves — very thick but warm and durable – $33
• 100% Yak Wool “Warrior”  Gloves — 100% Yak Wool – £50
• 100% Cashmere Gloves — a very soft and warm non-technical glove — $39

Warmest Hats

• 100% Qiviut Harpoon Cap — $195
• Khunu 100% Yak Wool Hat — $60
• 90% Bison Down Beanie — 90% bison down, 10% nylon – $85
• 100% Cashmere Cable Knit Hat — $40
• Cecilia Women’s 100% Alpaca Beanie — $64

Warmest Scarves

• 100% Qiviut Heavy Weight Aleutian Scarf – $275
• 100% Qiviut Handwoven Women’s Scarf – $275
• 100% Vicuna Scarf – $1495
• 100% Guanaco Scarf – $720
• 90% Bison Down Knit Scarf  – 90% bison down, 10% nylon – $125
• 100% Royal Alpaca Scarf – $99
• 100% Cashmere Scarf – $60

Warmest Base Layers (Top)

• 100% Yak Down ShoLa 230 Crew – $164
• Icebreaker Tech Top Long Sleeve Crewe (260 gm superfine merino) – $99

Warmest Base Layer (Leggings)

• 100% Yak Down Kora ShoLa Leggings – Men’s – $145
• Icebreaker Men’s Apex Leggings – (260 gm superfine merino) – $99

Warmest Sweaters

• Khunu 100% Yak Down Sweaters – $270
• Icebreaker 100% Superfine Merino Wool Sweater – $200
• 100% Royal Alpaca Fuoco Sweater – 100% Royal Alpaca – $231
• 100% Cashmere Half Zip Mock Neck Sweater – $129

Warmest Throw Blankets

• 90% Bison Down Blanket – 90% Bison Down and 10% Acrylic – $500
• 100% U.S.-Raised Alpaca Blanket Throw – $253

Warmest Bed Blankets

• 100% Qiviut Knitted Blankets – from $2,000 to $10,000
• 90% Bison Down Queen Size Blanket – 90% Bison Down and 10% Acrylic – $3,500
• Oversized King 70% Lambswool, 30% Merino Blanket – $427
• 80% Alpaca Twin Size Blanket – 80% Alpaca, 20% Ecuadorian wool – $259
• Oversized King Blanket 90% Alpaca, 10% Angora Mohair Blanket – $435
• Oversized Mohair Blanket – 67% mohair, 29% wool, 4% polyimide – $319
• 55% Alpaca King-Size Blanket – 55% Alpaca, 45% Wool – $250
• 100% Australian Merino Wool King Oversized Blanket – $294
• 100% Alpaca Wool Very Thick Blanket King Size – $119

Fibre Reference

Fleece & Fiber Sourcebook — this book explains the many types of animal fibers in the world