Columbia Omni-Heat Midweight Baselayer Crew review: a revolutionary first layer for icy adventures

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Columbia Omni-Heat Midweight Baselayer Crew: first impressions

Columbia introduced its Omni-Heat technology back in 2010, which takes the NASA-inspired technology that is used in emergency blankets and applies it to apparel. But like most technology, it's taken a few tries to get it right and lately, the company has taken some big strides. First, there was the ultra cozy Arch Rock Double Wall Elite Insulated Jacket which can fend off practically any amount of chill, and now there's this toasty base layer .

Made using elastane stretch jersey, the outer of this base layer gives a smooth, simple appearance, but it's what's on the inside that counts. Lined with tiny silver dots that look like foil everywhere but under the armpits, this base layer is designed to keep recycling your body heat while allowing water vapor to escape thanks to Omni-Wick fabric and the spaces between the dots.

• List price: $55 / £45
• Gender specification: Men's and women's sizing available
• Sizes: Men's S - XXL, Women's XS - XXL
• Weight (Small): 4.9 oz / 140 g
• Materials: 85% polyester, 15% elastane
• Colors: Black, Fig, Nocturnal
• Best use : Hiking, Winter sports

A foil-lined base layer really might not sound very comfortable, but trust us –  this one feels good against bare skin. Though it's listed as midweight, it's pretty light, making it really easy to layer and move in thanks to four-way stretch and ergonomic seaming.

It's a synthetic top, so it's going to get smellier than one made using merino wool , but a zinc-based antimicrobial treatment helps to hold off the laundry cycle and you can definitely sweat in it several times before it needs a wash. It doesn't have thumb holes and it's not made using any recycled materials, which is always a pity, and obviously it's not designed for warm weather hikes, but for cold weather? It packs a real punch.

Columbia Omni-Heat Midweight Baselayer Crew: in the field

I was a little late to the game with Omni-Heat technology, only discovering it last year in the Arch Rock Double Wall Elite Insulated Jacket which is so effective I actually keep it in my car now in case of emergencies.

I recently traveled to the Swiss Alps with Columbia to test out some of their new gear and this was one of the items I received. I'll admit, when I pulled it out of the box and saw the shiny lining, I was a bit skeptical. However, I dutifully took it to the mountains where I wore it for very chilly sunrise yoga as well as some high altitude hiking , and more recently I've been wearing it in the Cairngorms of Scotland for my hikes now that the weather has turned colder.

Here’s how it performed:

Sizing, fit and comfort

I tested a women's small, which is my usual size, and it's a perfect fit – snug without being too tight. Now, it does have loads of stretch, so there's some wiggle room, but I'd recommend just ordering your usual size if you want a close-to-the-skin fit that's easy to layer and does the best job of wicking sweat.

I like the high crew neck, which meant I got good sun protection recently when I ended up removing my jacket on a bright day.

Surprisingly, the lining isn't at all uncomfortable and in fact, I wore this top with the matching long johns for yoga and it felt great against my skin. It's light, soft and stretchy without any rubbing anywhere.

Temperature regulation and breathability

Obviously, this base layer is designed for warmth, so while I wouldn't wear it in the summer, I'm finding it great for any temperatures from just cool to really frigid. That's because it's really breathable , thanks in part to the omission of reflective lining under the arms as well as really breathable fabric. So even when I was hiking up the steep slopes of Ben Vrackie last week at 1,000 feet per mile and wearing a fleece over the top, I didn't overheat.

In fact, though I was sweaty in the usual places (underarms and where my backpack sits), I didn't even feel particularly damp. When I arrived at the summit, it was really breezy and cold, so I had to pull on my waterproof jacket fast. I expected I'd have to rush off the summit, but the genius of this technology is that even when you're damp and it's cold and windy, it keeps reflecting your body heat back to you, so I quite happily sat and ate my sandwich.

I only had to walk about a mile down the trail before I had to remove my outer layers again, and I noticed that the shirt had dried out really quickly. Obviously I wouldn't wear this for a warm summer hike, but I think it's brilliant for colder conditions and light enough to be layered or worn alone if it's mild out.

Odor control and other features

Odor control is always an issue with synthetic tops, and it's one of the reasons I usually go for merino wool, but this one is treated with an antimicrobial substance and I have to admit that it works quite well. I've had several outings without needing to put it in the laundry, though I'm not sure what the durability of these types of treatments is.

It doesn't have any thumb holes, and I know these are a feature many people look for in base layers. Personally, I think the sleeves are tight enough I don't need them for layering, and because it's for cold weather, I'd typically be wearing it with gloves or a fleece with thumb holes anyway.

Columbia Omni-Heat Midweight Baselayer Crew: the bottom line

If you want a seriously warm base layer that's not merino wool, look no further than this one, which blends state-of-the-art insulating technology into a breathable, straightforward and comfortable first layer. This top is built for cold weather, whether you're hiking, skiing or ice climbing . If you're still on the hunt for something super warm and want a merino blend that's great for sensitive skin, compare it with the Helly Hansen Lifa Merino Midweight Crew.

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