Reversible Hoody Can Be More Breathable or Warmer: Mountain Hardwear AirMesh Review

A thick layer of clouds descended as a friend and I scrambled to pitch the kitchen tarp deep in the backcountry. I quickly donned my fuzzy new midlayer — Mountain Hardwear’s AirMesh Hoody — before the hail started coming down. It gave me just enough warmth to fire up a round of backcountry bruschetta in the frigid late summer downpour.

The AirMesh Hoody got the nod because it packs down smaller than my grid fleece layers, and space is at a premium in my backpack. Its soft, fuzzy interior against my skin was a huge bonus on a frigid night of camping above treeline when my lightweight mummy bag needed a little boost to keep me warm.

This garment turned into my go-to midlayer all summer, especially as it started getting chillier at night. Bikepacking, backpacking, camping, lounging around on my couch — it proved more versatile than others like it.

The AirMesh Hoody’s versatility comes from its unique reversible fabric. One side keeps you warm and fuzzy, and the other keeps you cool and breezy. I wore it nonstop for three months to see how it would hold up through a busy summer in the mountains.

In short: Mountain Hardwear’s reversible AirMesh Hoody uses insulating hollow yarn on the inside. Mountain Hardwear claims there’s a 28% difference in warmth depending on the orientation. When you need more breathability, simply turn it inside out. It’s a versatile layer for backpacking, camping, hiking, and almost any other activity. However, I did find a few scenarios where it couldn’t outcompete my tried-and-true grid fleece.

Compare the Mountain Hardwear AirMesh Hoody to others in GearJunkie’s guide to the Best Merino Wool Shirts and the Best Sun Shirts.

Mountain Hardwear AirMesh Hoody Review

When I was first handed this hoody in a bundle, I thought it must be some kind of sun shirt until I felt the fuzzies on the inside. It’s almost like a fuzzy sun hoody. It’s lofty and really dang light for its volume at 181g in size large (fabric weight 115 g/m²).

Mountain Hardwear has been sneaking techy features into casual-looking layers for years. The Kor Alloy Crew is a tech-forward sweatshirt that I basically lived in last winter. Given its casual aesthetic and cut, you wouldn’t know it from afar, but the AirMesh Hoody follows suit. At 6’1” and 195 pounds, the Large AirMesh Hoody fit me perfectly. 

Reversibility

The headline of the AirMesh Hoody is its reversibility. But honestly, I haven’t been wowed by a single reversible layer for at least a decade, so I wasn’t holding my breath. They usually fit and look weird. But the AirMesh Hoody cleared my admittedly low bar. It fit and looked natural, regardless of which side was facing out.

But the real hook is the performance differential between the two sides of the main fabric. Mountain Hardwear claims that the fuzzy side is 28% warmer when worn on the inside, so logically, the mesh side is 28% cooler. Either way, I run hot, and I was pretty excited about the possibility of a midlayer that I could essentially dial up or down depending on the ambient temperatures and the activity at hand.

I tested the AirMesh Hoody’s reversibility claims repeatedly for months in the backcountry and frontcountry alike. The verdict? It’s subtle, but fuzzy-side-in is distinctly warmer than the other way around. I’d need a laboratory to pin down whether the 28% difference is marketing math or science. But for most users on the trail or in the woods, 28% felt about right.

Fabric Structure

The two sides of the fabric are quite different. The non-fuzzy side is a brushed polyester mesh with a smooth finish. Unlike your typical grid fleece, there are lots of big holes in the fabric, like a jersey knit. But the holes in the fabric are bigger. Each of those tiny black dots is actually a hole whose margins are black thread.

The fuzzy side is where things get interesting. The fuzz in the new AirMesh Hoody is a proprietary formula that gives this hoody its warmth-to-weight prowess.

The key characteristic is that the fuzzy yarn is hollow. So there’s a tiny little air pocket in each thread — not unlike an elk’s insulating hollow hair coat. Insulation works by trapping air close to the body, so in theory, hollow yarn captures a little bit of extra insulating air next to the body to boost the fabric’s warmth.

Mountain Hardwear is the only brand using this exact material, in this structure, in this execution. Fabric junkies will recognize other hollow-threaded fabrics on the market, but the brand’s designers found that this specific formula hit the density and weight targets that they were after. And what the AirMesh Hoody does that others don’t is flip inside out to allow the user two warmth options.

Breathability and Moisture

This hoody is exceptionally breathable for an insulation layer, especially when worn with the fuzzy side out. I don’t have a lab to rigorously test the AirMesh Hoody’s exact breathing capacity, but I have tested it in a few different scenarios that give me a pretty good idea of its capabilities compared to other midlayers in my arsenal.

Once I got up to speed after a few miles on a surprisingly cool September morning run, I could feel myself getting hot. But more so, I could feel the air flowing through the lightweight layer. Every gust of wind cut through the layer to cool my skin. It’s not a sensation I get with most other midlayers. It’s legitimately ultrabreathable insulation.

In that same way, icy wind cut right through it while I was fishing at a high alpine lake in Colorado. It’s distinctly not a wind blocker — I paired it with a light shell when I needed to block really chilly gusts.

But here’s the catch: Despite being exceptionally breathable, the AirMesh didn’t handle lots of sweat particularly well, and I’m a very sweaty guy. So once I worked up enough sweat to wet the fabric, it typically stayed wet for a while rather than quickly evaporating.

The same went for when I got blasted by a quick but intense rainstorm. It didn’t dry as quickly as I would have thought, given the synthetic fabric.

My suspicion was confirmed while hiking with a backpack, too. Once I pulled my pack off, my back was wet (as always). But it seemed to take longer for the AirMesh Hoody to dry than a grid fleece or sun hoody.

There’s something about the fuzzy side of the fleece that holds onto more moisture than other synthetic fabrics. So I wouldn’t call the AirMesh Hoody an all-star sweat-wicker, even though it is quite breathable. The same goes for adventures in wet weather. I aimed to keep it dry like I do with my down layers to ensure it could keep me warm when I needed it to.

Warmth vs. Weight Comparison

When worn with the fuzzy side in, the AirMesh Hoody felt significantly cooler than my other favorite midlayer, the classic Patagonia R1 Hoody (289g) or a similar-weight fleece. The AirMesh was a similar warmth but loftier and about 36% lighter than a lightweight microgrid fleece like Mountain Hardwear’s Crater Lake Heavyweight Hoody (275g in size L).

On the flip side (literally), it was a big step up in warmth from a sun hoody like my Black Diamond Alpenglow Sun hoody (244g). It occupies the warmth space between those two layer types while managing to be significantly lighter than all of them.

So rather than being exceptionally warm, the AirMesh Hoody’s warmth-for-its-weight is where it beats out its competitors.

While we’re comparing, I’ll note that the AirMesh is very lightweight and not particularly durable, given the open mesh weave. After some light bashing through the forest, a tree branch easily punctured the shoulder, leaving a nickel-sized hole, before I started treading a little more carefully. Grid fleece midlayers tend to be much harder-wearing.

Hood and Other Features

The AirMesh Hoody packs in a few simple features. The hood is top-notch — fuzzy on the inside and mesh on the outside, like the rest of the fabric. But I like the way it fits. It’s relatively loose, like a Melanzana hoody rather than a SCUBA hood that most grid fleece layers, like the Patagonia R1, have. It was just roomy enough to fit a helmet underneath, but also fitted enough that it didn’t blow off with a strong breeze.

When it was chilly, I basically lived with it on my head for a little boost of warmth.

The hoody also has a small zippered pocket on the left hip, big enough for a small wallet. I didn’t use it often, but it was low-profile enough not to feel excessive.

The last feature is thumbholes on each sleeve that help cover half of your hand. I appreciated the extra warmth and sun protection. It’s nothing particularly innovative, but it’s worth mentioning.

Mountain Hardwear AirMesh Hoody: Conclusion

The Mountain Hardwear AirMesh Hoody is both impressive and refreshingly weird. It felt like an almost perfect blend of a sun hoody and a fleece midlayer. With the fuzzy side out, I could bask in the alpine sun and enjoy moderately aerobic activities like hiking and light jogging without overheating. With the fuzzy side in, I felt warm without getting clammy.

It’s the type of layer that makes a lot of sense for a huge variety of mountain endeavors, from fishing to backpacking, especially when warmth-to-weight is a top priority. That it packs down so small is a big bonus for the activities that require stuffing it into a backpack for extended periods.

The catch is that it doesn’t manage moisture particularly well. And it’s fragile enough that tree branches are a legitimate hazard. Once I accepted those small tradeoffs and deployed it correctly, I thoroughly appreciated its versatility across the board.

Will it replace my beloved grid fleece midlayer? Probably not, especially when chilly weather, sweat-inducing activities, like ski touring, are on the itinerary. But I’ll be honest, my grid fleece hasn’t emerged from the closet since this AirMesh Hoody showed up earlier this summer. It edges out other midlayers when space is limited and temperatures fluctuate between warm, cool, and chilly.