Meriwool Midweight Thermal Review

As a relative newcomer to Merino-scene, Meriwool produces high-quality base layers at an affordable price point that stands in direct contrast to much of the marketplace. As our first experience with this brand, we chose to test the Meriwool Midweight Thermal, a competitive 100% Merino baselayer with a midweight-standard fabric weight of 250 g/m².

Performance Comparison

Even on a chilly, alpine morning, this base layer kept us warm and comfortable from sleeping bag to the trail.

Photo: Jill Rice

Warmth

As soon as we lifted it from the box, we knew that this was a base layer able to stand up to even the best of the competition. Although the 250 g/m² fabric weight puts the Meriwool Thermal at the top-end of our midweight selection, actually wearing this top suggests otherwise. It is curiously more lightweight than other, similar tops, making it more adept at thermoregulation than most. Even on warm, fall trail runs with lots of vertical gain, we never felt overheated while wearing this as a single layer. And as the seasons transitioned, we had no issues waking up and walking through frosty fields while backpacking in the alpine.

Despite the relatively similar fabric weight to other tops we tested, it does seem that the extra-fine Merino chosen to knit this layer makes a difference when it comes to warmth. It is not as warm as its direct competitors — we were noticeably colder, particularly when wearing this layer as a standalone top. For shoulder-season activity and into the winter, this is a great option. But don't be surprised if it comes up a bit short on the coldest days in the deep of winter.

Coffee warms from the inside, this layer effectively helps keep us warm from the outside.

Photo: Jill Rice

Breathability

Where this top falls a bit short in terms of overall warmth, it picks back up when it comes to thermoregulation thanks to impressive breathability. Merino wool is known for its incredible moisture-wicking ability, and the efficiency with which the fabric passes sweat from the inside to the outside for evaporation. The extra-fine Merino yarns chosen for the Meriwool Thermal's weave only improve that efficiency. For intense training sessions in cool-to-cold weather, this base layer pairs effectively with a lightweight shell, like a windbreaker.

For a layer with a density of 250 g/m², we must admit it performs much more similarly to those midweight base layers on the lighter end of the spectrum at around 200 g/m², for instance. As breathability tends to trend oppositely to warmth, it is no surprise that the small tradeoff the Meriwool Thermal makes in terms of warmth, it gains back in breathability. If you plan to be working hard—whether it's skinning uphill or chopping wood—this top is an excellent alternative to thicker baselayers we tested at the same or similar fabric weight.

Even on sun-blasted uphills during long, fall trail runs, we were seriously impressed with the performance of this layer.

Photo: Jill Rice

Comfort and Fit

Plush, but not too thick; soft, but not too delicate; the Meriwool Thermal seems to find that Goldilocks zone of comfort. Although we admit that the finer wool threads were a bit itchy at first, they quickly began to soften through regular wearing and washing.

Flatlock seams across the majority of this top—with the exception of the hem—ensures that the seams won't rub when worn next-to-skin. In the future, we hope that Meriwool updates this otherwise well-designed piece with off-the-shoulder seams. But this slight criticism was only noticeable under the weight of a heavy backpacking pack.

This top has a slim, athletic, and yet stylish fit that is as suited to a day on the mountain as heading into town. It appears to fit very true to size — a size Medium perfectly suited the 5'10", 155lb, slender and athletic frame of our head tester. We particularly appreciated that the well-cut arms end in cuffs that are supported by a slight elastic band. Unlike other tops in this review, the cuffs maintained their true shape longer, even when we continued to pull them up over our forearms.

A 360-degree view of the handsome fit of the Meriwool Midweight Thermal. Our head tester is 5'10", 155lbs, wearing a size medium.

Photo: Jill Rice

Drying Speed

As we have noted a few times already, what makes the Meriwool Thermal a standout among otherwise very similar, midweight options is the extra-fine spun Merino wool. As with increased breathability, this also translates to slightly faster drying times. Although it is not nearly as quick-drying as lightweight summer models we tested, there is a noticeable difference compared to its direct competition.

Indeed, the laboratory results from our soak n' dry test translated to what we experienced in the field while wearing this top as a base layer. Moisture was quickly wicked up and efficiently evaporated, keeping us dry and comfortable even through intense activity. The only exception to this was when backpacking—but without a suspended frame backpack, is it even a reasonable assumption to end the day without a sweaty back?

Similar to our Editors' Choice Award winner, the Meriwool Thermal has a hang-tag for drying. We love this feature, especially for Merino tops, because it keeps them from developing odd stretch marks around the collar.

Photo: Jill Rice

Durability

We had some initial doubts about the durability of this layer, again based on the underlying difference of the extra-fine spun merino wool. As a natural fiber, merino wool is not normally categorized as one of the more durable options for athletic attire. But through years of field testing wear-and-tear, we are coming around to a sense that this is more of a generalization.

Like other Merino tops tested, after our overly-aggressive abrasion test, the Meriwool Thermal really only showed signs of minor surface scarring. This finding is solidly backed up by some lumps and bumps we accrued mountain biking in this top. Our point is, don't always believe the hype. Thanks to flatlock seams backing up the high-quality construction of this layer, it is more likely to meet an early fate through improper washing and drying than it is through outdoor activity.

Breathable enough to tackle the uphill, and still strong enough to impress our testers.

Photo: Jill Rice

Layering Ability

As an athletically cut base layer, the Meriwool Thermal layers exceptionally under just about every mid-layer we tried. From sweaters to lightweight puffys, this slim fit top allows for a comfortable range of motion in every circumstance, making it both versatile and wildly practical. Although it doesn't involve layering directly, we received more than one compliment when wearing this top.

Since this top is designed first-and-foremost as a base layer, we certainly did not knock the Meriwool Thermal too much for its inability to comfortably layer underneath. We simply found that even while wearing a t-shirt, the upper arms become way too tight, verging on the point of restricting some particular movements. But it is important to mention, as there are other, similarly weighted tops we tested that do not have this issue.

Comfortably layered underneath a thick sweater, this base layer is sure to help keep you warm around the campfire.

Photo: Jill Rice

Value

This is where the Meriwool Thermal is truly exceptional — a quality, 100% merino wool base layer at a fraction of the cost of every other Merino layer we tested or researched. Without a doubt, this top is a great way to experience for yourself just why merino products are hyped as must-haves when it comes to technical base layers, without having to spend much more than a performance-driven synthetic top.

You might expect some concessions based on cost alone, but this quality top performs nearly as well as our top-contenders for a much more reasonable price.

Photo: Jill Rice

Conclusion

Style, breathability, top-quality craftsmanship, and above all, affordability characterize the Meriwool Midweight Thermal. As an up-and-comer in the 100% merino wool game, we initially loved the price but were skeptical it would truly perform. We're happy to report that this top's performance exceeds its price tag, offering great value and more affordable thermoregulation.

Waking up at sunrise to tackle a long-approached alpine climb. Make sure you don't hit the snooze button on buying this top-quality Merino base layer.

Photo: Jill Rice