The Smartwool Merino ¼ Zip baselayer is our go-to for outdoor play. The fabric is super cozy and warm, providing a wide range of thermoregulation through all four seasons. This Editors' Choice winner is our top recommendation for its versatility and bomber performance while skiing the bumps and hiking up majestic mountains.
Performance Comparison
The Smartwool 250 Zip continues to crush the competition. It does exactly what a good base layer should. Keeps you cool when you're hot and warm when you're cool. A perfect layer for any adventure, even cozy cabin ones.
Warmth
Packing in 250-grams of merino wool, this midweight baselayer offers exceptional warmth.
It offers a wide range of thermoregulation. We tested in temperatures ranging from the mid-70s to the double negatives. In all situations, we found applicable uses! In Northern Ontario, the soft wool insulated and generated heat under a mid-layer and jacket, keeping us toasty while skating and lake hiking. In Colorado, we ran and hiked, noting the cozy wool did a great job wicking away sweat. When caught in a rainstorm, this layer insulated and still kept us warm. As a result, it thrives in all conditions, making it perfect as a wear alone piece in warm months and a base layer in the colder part of the year.
Cold weather in Northern Canada and Washington State had us testing in temperatures that dipped into the double negatives. Here we test on a lift at Mt. Baker when temperatures hovered just around zero degrees Fahrenheit.
This warmth is largely attributed to its warm heat-conducting fibers. On days where we went from hiking really hard to standing still for lunch, we didn't get cold. While the wool itself is incredibly insulating, it is as equally as breathable. During these aerobic events, we sweat. When that happens, if the base layer cannot release the heat, you get cold. This fabric and construction are able to do that really well.
If you prefer Smartwool products, they have a plethora of different weight options using similar fabric. Simply check out the different weights if you prefer more or less warmth overall.
Breathability
In addition to being warm, this layer is ultra-breathable. When considering all the different layers on an afternoon run in the winter, our go-to is typically this layer amongst some other synthetic competitors. Its tighter fit facilitates better wicking ability and sweat does not hang around in the fabric. Also, the zip neck provides better venting than other constructions.
When skiing in Alaska and running in the desert, we were able to test the limits of breathability. In a layered system, the 100% merino wool fibers do a great job wicking away moisture from the skin. This kept us dry. The same was true for our desert running adventures. In both cases, layered and as a stand-alone top, it performs well, breathing when needed. As a key function of any base layer top, it reigns supreme in this metric. Take it with you for any endeavor you decide to pursue.
Trail running during an after-work run. The Smartwool 1/4 Zip sufficed on this trip providing great thermoregulation.
Comfort & Fit
Oh boy…can we celebrate the coziness of this fabric for a second? The Smartwool ¼ Zip is a go-to for everyday adventures. We like to wear it everywhere, though its best place is in the backcountry. The merino wool that Smartwool uses is super comfortable and soft. It doesn't itch, even when wearing it against the skin for days on end. It doesn't get smelly and seems to dry super quickly. Also, it stretches just enough for a fit that every one of our testers loves.
We tested fit with a variety of testers from short to tall. This particular piece features a medium fit, with the hem coming down just past the hips. The arms are long enough for all body types, and size is true to fit. Since the fabric stretches, it doesn't confine through the shoulders or the bust.
A look at the fit of our Editors' Choice award winner.
Given the relaxed fit, we found that it could easily be worn all day long, for multiple days on end. Put it on underneath a jacket or overtop a tight tank top or t-shirt. Testers of all shapes and sizes agree that fit is versatile yet precise. Overall, the Merino ¼ Zip has excellent comfort features and "next-to-the-skin" comfort that will have you adventuring for days, weeks, and months. During our testing period, we brought this with us on an adventure as the sole piece of gear. It sufficed during a month-long backpacking adventure in Northern Europe.
Layering Ability
Layering can be a small pain with this top, similar to other Merino wool contenders. With a face fabric that features a soft and "grabbier" fabric, we often found it difficult to get an insulating layer over top that featured a fleece lining. That said, upper layers with a slippier face fabric did just fine.
The top features a thinner fabric design and long arms that make it easy to pull a midweight insulating layer over top. The arms are longer than other Merino wool options so they can be used to pull through without bunching. In addition, because it's not super fitted, a layer can fit underneath. Aside from that, we didn't observe it riding up for bunching in weird places while on the move. It also fits underneath a jacket nicely.
Here we wrestle on the Patagonia R1 that has a fleece-lined interior. The grabbier face fabric of the Smartwool 1/4 Zip baselayer makes it a little harder to layer than those with a more slippery face fabric.
Durability
Utilizing a 100% Merino wool construction, this contender is the most durable, especially compared to synthetic models we tested. While we did not observe any serious wear and tear during our testing period, we noted some stitching flyaways and pilling of the fabric after just a few washes. After three years of testing, though, our base layer is still going strong.
We wouldn't choose it as a wear alone top for high-friction sports like crack climbing or canyoneering as the fabric would instantly tear with intense abrasion. Instead, we would choose it for day hikes or wear underneath other layers.
While this top didn't earn any holes, we noticed some pilling around the wrists and some stitching fly-aways. That said, we've had this model for years, and while it shows some wear, it's still holding up fine and still our favorite all-arounder!
Value
While this top is not the most durable, it certainly holds its value with its wonderful comfort and thermoregulation. The top base layers are priced within the same price range, and this is our favorite. If you're going for a long-sleeve merino wool top, we recommend this base layer most readily to our friends.
Conclusion
This Editors' Choice winner is perfect for all-year-round play. Its wide range of thermoregulation in addition to its cozy fabrics will have you wearing it day-to-day. Take it with you on your next great adventure. And the next one. And then the one after that.
The Smartwool 250 1/4 Zip is our favorite base layer, offering supreme warmth and comfort through even the coldest of days of winter.
