Cold? I bet we can fix that. Staying warm in any condition — the office, the commute, a ski slope or in the outdoors — starts with a good base layer. Here's how to find the best ones for your individual needs.
What do base layers do? We asked Gerard Smith, Senior Global Product Designer at Icebreaker. "The idea of a base layer is to provide temperature regulation and to move any moisture away from your skin while you are active. It is your next-to-skin comfort layer, your foundation garment over which you can then layer mid or outer layers as weather and climate conditions dictate."
Base layers — long underwear — are capable of adding considerable warmth. So, layering a pair under your jeans for a winter commute will help keep you warm. But, choosing the right ones means you can then leave them on all day while sitting around your office.
If you're active in the outdoors during cold temperatures, a good set of base layers is even more crucial. They'll keep you dry as you sweat and help regulate your body temperature as you heat up during activities and then cool down during rest.
"The wicking process works by moving moisture away from your skin through contact with your base layer," explains Gerard. "The moisture then moves to the outside of your base layer where it spreads along a larger surface area where it can dry more effectively."
Materials: There's four main materials you'll find base layers made from, all coming in at different price points and with different applications. Let's look at each.
Synthetic: There's a huge variety of synthetic materials used in base layers. In general, bases made from these are very capable of moisture wicking and can add much warmth while remaining breathable. If you get them soaked, they'll dry faster than anything else. The downside? They stink. Literally, a single day in synthetic base layers is often enough to make them smell like a men's locker room.
Cotton: Affordable and actually capable of adding a fair bit of warmth. If you hold still that is. Cotton soaks up any sweat or moisture, then gets cold and clammy. To insulate, it also needs to be heavy and thick. Avoid if at all possible.
Silk: With a massive warmth-to-weight/thickness ratio, silk is an excellent choice for layering under casual clothing. Even women who want to wear tight jeans can often squeeze a silk base layer in underneath. Silk also feels as nice against your skin as it sounds like it will. Trouble is, silk doesn't have the same ability to remain comfortable in very warm temperatures as merino, meaning it may prove too hot to wear all day in a warm office. It's better at wicking moisture than cotton, but not quite as good as a quality synthetic or merino. Silk is also expensive. A great option for base layers covering your hands, feet or head, when any of those body parts may need to squeeze into another item of form-fitting clothing like shoes or a helmet.
Merino Wool: A true wonder material, this very soft wool is applicable to the widest range of temperatures here; the same set of merino bases can keep you warm on sub-freezing nights and remain comfortable as temperatures rise above 70 degrees. Merino also wicks with extraordinary effectiveness and strongly resists odor. I've worn the same set of Merino bases all day, every day during a week-long trip, even sleeping in them, and they never started smelling bad.
Note that all these materials come in a variety of weights applicable to different temperature ranges. Typically, the smaller the number, the warmer the temperatures they'll be designed to deal with and the higher the number and the heavier the weight, the colder the temperature range. For instance, I'll wear Icebreaker's 200-weight base layers when I plan to encounter temperatures above and below freezing on the same trip, opting for the 260-weights when temperatures won't rise above freezing. The higher the number, the warmer they are.
Which base layers are best for you? Let's envision some common needs and users and try to find the best long undies for each.
Who you are: Someone living in a part of the world with cold winters who works inside and just wants to be warmer, without dressing like an eskimo. Most of you.
Temperatures you experience: You commute to work in sub-freezing temperatures, then sit in a poorly heated office all day.
You want: Silk base layers. They won't alter the way you look in your fashionable clothes, while adding appreciable warmth. Look for ones that fit you tightly for the easiest possible layering. A crew neck is probably best for the top, so it doesn't protrude outside your normal clothes.
Who you are: You do battle with taxi drivers just to get to work, getting your daily exercise in the process.
Temperatures you experience: From rainy springs to frigid winters, you're out there pedaling furiously in the worst mother nature can throw at you.
You want: Lightweight merino wool base layers. Wear them under a water and windproof shell, adding a warm mid-layer when temperatures really drop and you'll be good to go. You won't overheat in them either while pedaling or sitting in the office and you can wear the same pair throughout a solid work week before you'll need to launder them.
Who you are: Someone with epic winter vacation plans.
Temperatures you experience: You'll be working hard for short periods, then sitting still on the lift for longer, all in very cold temperatures.
You want: Heavyweight merino wool base layers. They'll keep you dry as you work up a sweat, then keep you warm once you're sitting still. Layering effectively will be a big help here, look for mid-layer and shells that work similarly.
Who you are: From being active outdoors to layering up on a cold day, you're just looking to stay warm without breaking the bank.
Temperatures you experience: Who cares, it's cold outside.
You want: Synthetic base layers. The stuff you buy from the army surplus store are going to be the cheapest option, or maybe Uniqlo. Those are actually quite effective at keeping you warm, but you'll overheat the second you step inside a warm building or vehicle. Spending up to one of the big outdoors brands should add a little more variability to your temperature range.
Who you are: Cars are mass-insanity. They just get stuck in traffic, are ridiculously inefficient to use as personal transportation and are boring to drive. What's a little bad weather in comparison to that?
Temperatures you experience: Cruising at 85mph on the highway, windchill can make 32 degrees feel like zero. You need the absolute best insulation possible.
You want: The heaviest synthetic base layers possible, preferably with a windproof membrane built into them. I use the Arc'Teryx Phase SV stuff, occasionally alternating with an old set of Mountain Hardwear stuff that includes Gore Windstopper. Look for a top with a high neck to extend insulation across as much of your body as possible. You'll also want to add some neck insulation (I use an Aerostich Silk Scarf) and a good silk balaclava, which unlike thicker materials, won't require a poorly fitting helmet to be comfortable. Layer with the warmest mid-layers possible (polar fleece sweatpants are perfect), consider a heated vest and heated grips, and wear all that under a one-piece Aerostich Roadcrafter and you might not lose any fingers.
Stop looking to base layers as your main source of insulation and buy a quality down jacket. Layer that under a wind/water proof or resistant shell, cover your head and neck and you'll be good to go. It's the job of base layers to regulate temperatures and keep you dry, not provide all your insulation.
Every brand has its own unique selling point that they'll disguise as fancy technology or heat reflective dots or whatever whizz bang feature you care to come up with. They're still just a base layer made from one of the above materials. Pick the right material for the job, choose the appropriate weight for your own unique needs then find a set that fits you tightly.
"It is important that base layers fit snugly," says Gerard. "This enables the next-to-skin microclimate that ensures wicking takes place and keeps you comfortable."
Photos: Chris Brinlee Jr.