The Arc'teryx Rho is our Top Pick amongst synthetic long underwear bottoms. It can be worn all four seasons, either on its own or with a layered outfit. Wear it while crushing the alpine on a pair of skis or while casually lounging around the house with your favorite book. It stands out for its cute colors and streamlined look that can easily be worn on its own. Of any synthetic contender, it is superiorly hydrophobic that will keep you dry while hiking up a mountain or snuggling in your sleeping bag.
The Arc'teryx Rho LT offers amazing performance across the board. It's our favorite for chilling out at the chalet, skiing, hiking, and climbing. We love its cute look and quite affordable price tag. It's also super durable.
These bottoms are warm and cozy, best for cool to cold weather. We stacked them underneath thin Gore-tex snow pants, wore them on their own, and slept out in cold weather. Built with 150-grams of synthetic Torrent fleece (84 percent polyester, 16 percent elastane), it does a great job at wicking away moisture to keep you dry while on the move. In addition to warm fabrics, the outer fabric is tough and smooth, offering an additional level of thickness that provides even more warmth. Even though these bottoms are deemed "lightweight" by Arc'teryx, they feel more like a "midweight" construct offering a similar level of warmth to other products in this category.
In our testing experiences, we were happy with the provided warmth of these gorgeous and comfortable long underwear bottoms. While out skiing, the materials were thick enough to be the only insulative layer under a thinner pair of non-insulated Gore-tex pants.
The fabrics are thin but cozy. The outer face fabric provides a little more durability while the inner fleece wicks efficiently to ultimately keep you warmer on cool to cold days.
On this particular day, the temperature hovered just around freezing. While we were pretty comfortable, this was mostly due to well-ventilating pants. It's essential to vent out sweat and heat as the fabric itself will keep you warm, but will also absorb a little moisture, decreasing warmth overall. Also, because the materials aren't super thick, if we were to go to the ski resort and sit on a cold chairlift for minutes on end, we'd probably opt for an additional insulative layer..especialy if double negatives were in the forecast. Overall, we give this product a big thumbs up for warmth.
A look at the soft inner fleece, and the outer face fabrics.
Since it is easy to layer, wear it under everything from a pair of stretchy skinny jeans to your biggest insulated snow pants. Or wear it on its own. The face fabric does a decent job at cutting a sharp wind, offering warmth in both layered or on its systems.
Jack and I stayed nice and warm on the summit of this 14,000 ft peak. We went from running and sweating to sitting in the cold. In both conditions, the material wicked and thermoregulated perfectly.
Boasting great breathability, this long underwear will keep you dry, even on some of your sweatiest endeavors, as long as there is proper ventilation. While the fabrics are thicker than other contenders in this review, the fleece does an exceptional job at grabbing sweat and wicking it away to the outside of the fabric. Fleece is soft and the fibers allow a porous surface that easily absorbs the moisture and transports it away from the skin assuming proper ventilation.
When wearing this baselayer with a pair of pants, it did a great job at wicking but absorbed more water than other contenders (~11.95 oz). We found that without proper ventilation, sweat retains in the fabric and lingers over time. Our water resistance and drying tests confirmed this. As opposed to other synthetics, when the Torrent material had some moisture poured on the face fabric, it beaded nicely for a more extended period. In comparison to other synthetics, the Torrent fibers are more hydrophobic at first. However, when agitated, it absorbed a lot more water. That said, in our drying tests, it proved to dry quite quickly…which is a natural property of polyester.
Unlike other synthetics, the fleece fabric does a great job to bead up water instead of absorbing it.
In our field tests, we hiked and ran to see how the materials worked in the field. We tested it while running up a giant mountain in Colorado. The day offered a wide range of temperatures and conditions. As we rose from 9,000 feet and climbed to 14,000 feet midday, we encountered warm temperatures at the parking lot, sweaty conditions up the trail, and cold, windy weather at the summit.
Here we run up mountain tops in Hawaii on a warm morning. This layer offers amazing breathability that kept us warm and protected on top of these scenic peaks.
Through it, the fabric regulated temperature very well. When we began to sweat, the heat was effectively released and the sweat was wicked away nicely. For increased ventilation, we rolled up the bottom. After toiling on the trail then hanging out at the top of the mountain in windy and cold conditions, we didn't feel clammy or cold. However, when we put this pant together with a layered system and we sweat profusely for about an hour, we found the material stayed clammy if there was no ventilation with the upper layer. As a result, we'd recommend layering this warm and breathable base layer with a pant that will allow you to ventilate heat and sweat appropriately.
Comfort and Fit
Man alive, this bottom is hard to take off! Arc'teryx uses Torrent fleece in its construction. The interior of this fabric uses a fluffy and compact fleece layer that does the most amazing job wicking moisture away from the skin. The outer fabric is soft to the touch and smooth, allowing you to easily layer it underneath tight, grabbier layers. The waistband rides high but is very wide and amazingly comfortable for all-day or nightwear. The fabric itself integrates Elastine into the polyester that makes the fabric bounce back into position and shape, even after a long day out playing in the snow. To top it off, the seams are all flat so they don't chafe after long days worth of wear.
So what about fit? Given that the fabric is incredibly stretchy, it conforms to all shapes and sizes! At the ankles hem and the waistband (where the fit can be limiting), the fabric continues to stretch way out!
When asking a variety of women to try on these bottoms, we learned that all of them appreciated the fit: tall, short, thick, thin. No weird areas of constriction and the size is true to fit. The crotch is gusseted which ensures no odd lines, just a smooth, nice-looking appearance. The only piece of feedback worth mentioning is the legs are long. Many of the shorter testers even rolled up the bottoms of the pant — which was no big deal. The long and short is that it provides excellent coverage throughout the leg.
A look at the relative fit of the Arc'teryx Rho LT bottoms. The design is inconspicuous and can pass as a running pant, easily worn on its own in public.
In our experiences, this bottom was our absolute favorite for lounging around the house. Because of its ultra-cute colors and streamlined look we also typically wore it on its while running chores. Given that the material doesn't lose its shape, even after running in it for hours, this bottom is also a top choice for wear on its own. All these essential features make it our Top Pick. It had our testers jaw-dropped and googly-eyed, fighting over who got to wear it throughout the day.
The longer lengths are perfect for all sizes! Simply roll up the cuff if you want a little more ventilation.
This is a highly durable long underwear base layer that isn't especially prone to snags. The fabric, unlike merino wool, doesn't rip easily. The materials itself didn't pill during our testing period, even after washing it several times on low and high heat. The stitching seems to be flawless, offering an exceptional level of craftsmanship, typical of Arc'teryx products. Even in cases where we wore a harness for extended periods of time or had a part of a Gore-Tex snow pant rub against the fabric all day, no noted signs of wear and tear existed throughout this three month testing period. So we conclude that (like other synthetics) it is exceptionally durable and will last you for many years to come. This is another reason it earns a Top Pick.
While the construction of this product is impeccable, it's not infallible. Like all base layers or long underwear, it is intended to be worn underneath other articles of clothing. Arc'teryx did a great job of making it more versatile for wear on its own with its cute colors and its bomber construction. While the fabric is quite burly for a comfortable long underwear bottom, it can still attain holes and wear over time. While testing this bottom on a run-up Uncompahgre Peak (a 14,000-foot mountain in Colorado) we took a huge and hard fall on the trail when wearing just this bottom. We scrapped our hands and landed hard on the knees.
A little tear in the fabric after a big fall on the trail.
During this experience, the Rho LT fabric got put to the test. Instead of earning giant holes (that we would have expected with Merino contenders), it only got two small holes, one on each knee. This layer proves to be a little more robust than the rest…mostly due to the thickness of the fabric, the exceptional craftsmanship, and synthetic construction. After two years of intense testing and wear, it still does amazing work, keeping us warm and comfortable on the trail.
A look at the nice stitching and lines that give this pant style points.
The fabric doesn't smell over long periods of wear. We are stoked for this cool feature in synthetic fiber.
Arc'teryx is typically renowned for its expensive products but also its exceptional durability and value. We are surprised to learn that this bomber base bottom is comparable in price to other high performers. Also, the fabrics are more durable than merino wool contenders and the craftsmanship is quite impeccable. The value is amazing and despite the seemingly high ticket price, it is right on point for the performance and durability it offers. It's best if you prefer a synthetic fiber and want a pant that you can easily wear on its own or in a layered system.
Here we take the Arc'teryx Rho LT bottoms on hiking run up a mountain in the San Juans. We love this pant for all sorts of missions!
The Arc'teryx Rho LT Bottoms
are our favorite for lounging around the house and for wear on its own. Stacked with numerous performance features and does well in cool to cold temperatures. It's highly recommended if you seek a cute, well constructed, and comfortable synthetic base layer that will keep you warm through all sorts of conditions. We appreciate the lower price and high level of craftsmanship that has lasted us for two years and running!