The North Face Radium Hi-Loft Fleece Jacket
Size Tested: Medium
Zipper Length: 27″ (medium)
Days Tested: ~15
This jacket initially caught my eye late last winter when I saw Polartec’s announcement about their insulating fabric, Thermal Pro High Loft. After about 15 days testing it, I can say I think it is exceptionally awesome.
This fabric attacks the problem many insulators face: they’re either down or a synthetic-down copy.
The problem with down and most synthetics is that since the individual fibers are so fine, they require “down-proof” fabrics to contain them. These down-proof fabrics are high-density nylon weaves that, while light, hardly breathe at all.
Polartec’s Thermal Pro takes a different approach when it comes to insulation. The company created an extremely low-density knit fleece, which does what any insulator does—it traps warm air. But with Polartec’s new fabric, there’s no vapor barrier preventing breathability. Imagine wearing a thin down jacket where the down is simply suspended around you body with no nylon shell fabric…
Okay, the Radium isn’t exactly like that, but it’s fairly close. Compared to down, the Radium is heavier, substantially less wind resistant, and less packable. There are definitely some tradeoffs, which I’ll talk about in a bit.
So is Polartec’s Thermal Pro going to change the way the world looks at insulation? Probably not. Does it add another excellent option to the market? Absolutely.
One last note. Most of my comparisons in this review will be to more “modern” insulators (such as my Patagonia Nano Puff), as opposed to traditional fleece. The Thermal Pro High Loft is very different from a typical fleece jacket (think Polartec Polar Fleece like The North Face Denali). Polartec Fleece is heavier, substantially less packable, and less breathable. I have never been a big Polar Fleece fan for these reasons.
Thermal Pro High Loft, on the other hand, is warmer, more packable, and lighter.
I got the “Firefly Green” jacket, which turns out to be more neon yellow than green. The Radium is also furry, like a yeti, and it has horizontal stripes across the torso and arms. It’s accented with forest green Power Fleece. If you’re not a fan of bright, loud jackets, the Radium comes in more subdued colors as well.
And even though you might worry, like I did, that this jacket will leave your house covered in neon yellow fibers (as if you had a new long-haired cat that was spoon fed uranium as a kitten), the shedding is actually quite minimal.
Similar to Polartec’s other new insulating fabric, Polartec Alpha, the Thermal Pro is a low-density fabric. This means most of the fabric is empty space. In fact, when you take a close look, it’s actually almost transparent. Imagine a piece of mesh with large holes and long fibers of fleece woven throughout it. The “mesh” acts like a scaffold for the fleece to sit on.
Breathability (and Wind Resistance)
A jacket with a low-density fabric woven into a mesh scaffold? Does that sound like it might breathe pretty well? It does. The Radium is one of the most breathable jackets I have ever worn. This jacket breathes as well, if not better, than a thin cotton T-shirt.
Granted, this phenomenal breathability comes at a price. The Radium has almost zero wind resistance. The only places on the jacket with noticeable wind resistance are the panels of power fleece, so I hardly wore this jacket outside without a wind resistant layer over it. Even hiking on a still, cold day, I’d feel chilled because my swinging arms would generate enough wind to penetrate the jacket.
Warmth & Best Uses: The North Face Radium vs. Patagonia Nano Puff
The Radium is a warm jacket, but it is still pretty thin. I would say it is about as warm as my Patagonia Nano Puff, but not as warm as my loftier Montbell Ultralight Alpine down jacket. (As a rule of thumb, a jacket is as warm as it is thick with loft. The Radium is about as thick as the Nano Puff, so it is just about as warm as the Nano Puff.)
I think the Radium and Nano Puff represent the active and non-active classes of insulators. The Nano Puff is lighter than the Radium, 100% windproof, and breathes poorly. The Radium is a bit heavier, wind-transparent, and breathes like it isn’t even there.
I wear my Nano Puff as an alpine belay jacket in the summer, and as a general warm outerlayer in dry conditions. I don’t wear it skiing, hiking or climbing, since it just doesn’t breathe well enough. The Radium is the exact opposite. I wear it skiing, hiking and climbing (although I nearly always wear a hardshell over it). I do not wear it to stay warm during sedentary activities.
The Radium has a great fit for an active jacket. It is slim throughout the body (much more so than the Nano Puff) and cut long enough (27 inches) so that it can easily be tucked into a harness. The arms are cut long, meaning that your wrists and forearms will always be covered, even when you’re reaching for holds high above your head. The sleeves extend to the base of my fingers with my arms at my sides.
The Power Stretch panels on the sides of the jacket allow the jacket to move easily with you, and the Thermal Pro itself has some stretch to it.
Overall, the fit of this jacket is perfectly suited to complement the activities this jacket excels at. Compared to “standard” fleece jackets, I would say the Radium has longer arms and a longer torso, and it’s slightly slimmer in the body.
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