Glacial Gear Merino Wool Sleeping Bag Liner Review

The feeling of my sleeping quilt’s synthetic material rubbing against my skin gives me the heebie-jeebies. There’s just something about the faux-silk feel that makes it impossible to sleep comfortably unless I have a barrier between the quilt and my body.

This was the initial reason I began carrying a sleeping bag liner when working as a backcountry guide in Great Smoky Mountains National Park. This extra piece of gear may seem unnecessary to some, but with the Glacial Gear merino wool liner, my pack remains light and I can sleep soundly at night. 

Glacial Gear Merino Wool Sleeping Bag Liner At a Glance

hiker poses in shelter inside black glacial gear merino wool sleeping bag liner

Cozy in my Glacial Gear Merino Wool Sleeping Bag Liner.

MSRP: $175

Weight:

  • Small: 14.2 oz
  • Medium: 15.2 oz
  • Large: 16 oz

Size Range: Small, Medium, Large

  • Small: Fits up to 5’6″ (168 cm)
  • Medium: Fits up to 6’0″ (183 cm)
  • Large: Fits up to 6’6″ (198 cm)
  • Circumference at Shoulder for All Sizes: 56″ (142 cm) 

Materials: 100% New Zealand sourced ZQ Merino wool

Circumstances of Review

I packed a size medium Glacial Gear Merino Wool Sleeping Bag Liner for multiple overnight trips in the Smokies during my 2024 season working as a backpacking guide. The majority of these trips took place during the summer months, with nighttime temperatures ranging from 40°F to 70°F. Some of these nights were spent in shelters along the Appalachian Trail, and others were in the solitude of my tent.

This liner was paired with my Enlightened Equipment sleeping quilt.

Key Features

100 percent merino wool: This liner is made from 100 percent New Zealand sourced ZQ Merino wool, meaning it is lightweight, breathable, antimicrobial, and soft to the touch. More on merino wool properties below.

Large shoulder circumference: This mummy liner allows for optimal room while keeping you completely covered. “Mummy style” means that it has a narrower footbox and gradually increases in circumference moving from bottom to top. The total circumference at the shoulders is 56 inches. This allows plenty of room to comfortably move your arms in your sleep. I am a slide sleeper and found it easy to readjust while rolling from side to side at night. 

Glacial Gear Merino Wool Sleeping Bag Liner Overview

All snuggled up with in my Glacial Gear merino wool liner.

What’s the Big Deal About Merino Wool?

You’ve probably run across merino wool when shopping for hiking clothes. Many companies have shifted to merino because of its sustainability, breathability, moisture-wicking properties, and superior comfort compared to synthetics.

On the other hand, merino clothes usually cost more and are less durable.

Glacial Gear’s Merino Wool Sleeping Bag Liner is made from 100 percent New Zealand ZQ merino wool.

What does this mean? Merino is a type of sheep whose wool is sheared and spun into fibers to be made into our favorite products. Meanwhile, ZQ denotes wool that has been ethically and sustainably harvested. It’s like the Responsible Down Standard, but for wool.

Sustainability

Since merino wool comes from sheep, it is a renewable resource. One sheep can grow 4-5 pounds of wool a year, and ZQ sheep typically live for 6-8 years in the high country of New Zealand, where they are sheared regularly for their health as well as wool production.

ZQ Natural Fibers is the supplier of Glacial Gear’s high-quality merino wool, and they are dedicated to sustainable farming practices. Glacial Gear also partners with Responsible Stewardship to help educate people to be good stewards of public lands.

Glacial Gear is a midwestern small business started by husband and wife Shereen and Shane Petersen. Named after the couple’s love for their local natural area, Glacial Park the brand was born of necessity when Shane couldn’t find what he was looking for in the gear market.

The Petersens are passionate about creating high-quality products that are sustainability made and delivered in environmentally friendly packaging. In recent years they have teamed up with mega backpacking brand Zpacks to create ultralight trail rags and blankets

Glacial Gear Merino Wool Sleeping Bag Liner Pros

Using Glacial Gear’s liner as a blanket while sitting around the shelter.

Antimicrobial: This term is thrown around a lot in association with everything from pee cloths to base layers. Bacteria don’t flourish as easily on antimicrobial textiles. This helps limit the spread of germs and diseases and also keeps your gear from getting the infamous hiker funk by limiting the growth of odor-causing microbes.

This liner can go longer between washes because it’s less prone to developing rank odors than synthetic liners.

Temperature Regulating: Because of the makeup of merino wool fibers, Glacial Gear’s liner helps to regulate your body temperature while sleeping. Merino wool makes for a great insulator when it’s cold and wicks away sweat to keep you cool on hot summer nights. 

Moisture Wicking: Merino wool is effective at wicking sweat away to help regulate body temperature. 

Breathability: A key selling point for merino wool is its breathability compared to synthetic materials. Many synthetic fibers like polyester and spandex trap heat and moisture. In contrast, merino wool can absorb and evaporate moisture, keeping the material light and airy. 

Soft: Many backpackers carry liners solely to act as a barrier between their sleeping bag and their skin. I find merino even softer and more comforting than common liner materials like silk and fleece.

Stretchy: Merino wool is more generous when it comes to stretch. Similar synthetic liners have little to no give, but Glacial Gear’s liner has plenty of elasticity. I found this to be especially true when rolling side to side at night.

It helped the mummy design to feel less restrictive and like I had more room to breathe. Some people feel constricted in mummy-style bags and liners, but the stretchiness here meant there was room to wiggle and get comfortable.
 

Showing off the stretchy property of merino wool.

Glacial Gear Merino Wool Sleeping Bag Liner Cons

Extra weight: At 15.2 ounces for a Medium, Glacial Gear’s liner is comparable in weight to other liners on the market. For some folks, the comfort a liner provides is a no-brainer, but other hikers wouldn’t dare add such a frivolous luxury item. We’ve all heard the age-old phrase “ounces make pounds.” If you are ultralight to the point of cutting off your toothbrush handle, I don’t expect you to be carrying the extra weight of a sleeping bag liner.

Doesn’t add significant warmth: Glacial Gear’s wool liner will add a few extra degrees, but in my mind it’s mainly just for comfort. I tested this liner out in the summer months in the Smokies and it is a perfect standalone on those hot summer nights. I think there could be better alternatives if you were trying to add significant degrees to your sleep system. On my thru-hikes of the AT and AZT, I carried a fleece liner for extra warmth. 

No hood: One thing I think this liner is missing is a hood. Especially on a chilly night, I want to be able to pull the covers up over my head and get really snuggled up. Other mummy bags and liners come with a built-in hood. This was a feature I felt was lacking.

Tears easily: I took this liner out for several of my backpacking trips this summer, and by the second or third trip I noticed that it was already developing small tears. I washed the liner once according to the website’s instructions (“machine wash on delicate cycle/ lay flat to dry or tumble dry on low heat”).

I was disappointed by how fragile the liner seemed to be because I wasn’t overly rough with it. I curled up inside of it at night and used it as a blanket while sitting around camp — nothing out of the ordinary. 

Worth noting here that moths love to eat merino wool, making it even more vulnerable to holes and damage.

Small holes began developing after only a few trips into the backcountry.

Overall

If comfort matters to you, Glacial Gear’s Merino Wool Sleeping Bag Liner is a great choice for you. I slept great with the addition of this liner to my system. On the other hand, if you’re overly conscious about your base weight, maybe it doesn’t make the cut.

For me, it’s perfect for weekend trips, but I worry about how well it would hold up on multi-month journeys.

Shop the Glacial Gear Merino Wool Sleeping Bag Liner

Comparable Liners

Big Agnes Sleeping Bag Liner – Wool 

  • MSRP: $199.95
  • Weight: 16oz

Cocoon MummyLiner Merino Wool 

  • MSRP: $109.95
  • Weight: 22oz

Sea to Summit Reactor Fleece Sleeping Bag Liner 

  • MSRP: $99.95
  • Weight: 13.8oz

The Glacial Gear Merino Wool Sleeping Bag Liner was donated for purpose of review.

Featured image: Glacial Gear

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