Lightweight, packable, insulated jackets are a staple for a mountain lifestyle. But, don’t expect every one of them to perform across a variety of activities. The Rab Xenair Alpine Light Insulated Jacket is built for start/stop activities as an outer or mid layer. I have loved the fit, performance and overall function of the Xenair Alpine Light, but it can get overwhelmed during high-output adventures.
Rab Xenair Alpine Light Insulated Jacket Features:
- Pertex Quantum Air nylon outer shell
- Recycled nylon lining
- Body-mapped Primaloft Gold Insulation Active+ insulation
- DWR for weather resistance
- Two front hand pockets and single interior chest pocket
- Form-fitting, elasticized hood
- Cuff gusset for added comfort
- Single-sided hem adjustment
- Weight: 305 grams (medium, actual)
- MSRP: $215.00

A jacket in search of “start/stop” activities
Rab remains one of my favorite outwear manufacturers — with their optimized fit and performance materials being tops on that list. But, sometimes, even the best materials can have you unsuccessfully finding its intended use. Now, Rab does have the luxury of offering pinpoint outerwear for niche uses, like mountaineering, ice climbing, rock climbing, etc. But, as users, we demand versatility (almost to a fault).
That being said, Rab touts the lightweight and comfortable Xenair Alpine Light Insulated Jacket as being made for start/stop activities. Skiing would be a great definition of that. But, outside of that, I can’t think of many of my usual mountain activities that fall into that category. Unfortunately, a resort ski test hasn’t happened, but I have tested the Xenair Alpine Light Insulated Jacket winter trail running and hiking. I guess if 45 minutes of activity, then a long rest can be considered start/stop, then I’ve tested the intended purpose (but, I don’t think that’s what Rab meant).

Modern insulated jackets should all be body-mapped. That means that there’s more insulation where you need it and less where you don’t. with the Xenair Alpine Light, that means that it features 60gsm material through front, back, top of sleeves and collar and then 40gsm through sides, underarms, spine and top of hood. On paper, that all sounds great. And, in practice, that varied insulation makes for just the right comfort for low-output activities. Walking the dog in cold, 25-35 degree temps is acceptable with the right under layers, but don’t expect the warmth that a Montane Anti-Freeze Down Hooded Jacket can provide. I’ll add that neither anyone, nor Rab should expect it to. Where the Xenair Alpine Light should shine is warmth and comfort while moving in the mountains.

As mentioned, my primary movements have been hiking and trail running with the Xenair Alpine Light. No question, when slipping this jacket on, it feels fantastic. The fit is trim without being snug and the overall cut is fantastic. As always, I feel like the sleeves could be an inch longer for added coverage, but I wouldn’t consider them “short.”
The under-helmet hood is form-fitting and comfortable. It can be pulled on/off without unzipping, yet doesn’t have any extra fluff. I have a shaved head and it fits my noggin like a champ. Peripheral vision is maintained and the hood moves with you. I actually really like the elastic stretch gather in the back of the hood as opposed to a toggle system. It’s lighter and more streamlined. The collar sits at your chin to stay out of the way when breathing during any given activity. In a pinch, you can tuck your chin down into the jacket, but don’t expect full face coverage during foul weather.

Pertex Quantum Air fabric is excellent. With a smooth hand and quieter feel, I can wear this jacket all day in the mountains or around town. The shell fabric is very capable of weathering rain and snow, but isn’t waterproof. That said, it’s much more protective than you may think. But, a shell would be advisable if extended rain/snow is expected. For alpine skiing, a nice shell and the Xenair Alpine Light should be a great combo. In fact, that may be its best use-case.

Why don’t we get into my functional testing as a winter trail running jacket. When running in the mountains, usual temperatures are in the low-20’s. At those temperatures, I need something warm, but breathable. After about 20 minutes of running, the jacket gets to equilibrium as my body heats up and the jacket’s ability to expel moisture is tested. The best jackets on the market will get to that point and get a little damp, but not overwhelmed. Some of them increase ventilation with laser-cut underarm vents (Outdoor Vitals Ventus Active Hoodie) and others strategically place fleece fabrics there (Montane Icarus Flight Jacket). With the Xenair Alpine Light, Rab did vary the density of the insulation, but that’s not enough to allow this jacket to perform during high-output activities.
As mentioned, once I hit that 20 minute mark on any trail run or long hike, the jacket gets overwhelmed instead of reaching a comfortable homeostasis. By the end of a 5-mile run, the jacket will be completely wetted-out and saturated. At that point, a cold, stiff breeze and any stopping whatsoever brings an immediate chill. It’s then saturated enough that all I want to do is take it off for fear of chill.
With that, I wouldn’t recommend the Xenair Alpine Light as a dedicated trail running, snowshoeing or hiking jacket where you’re going to push it to its limits. Start/stop activities, like alpine skiing or light walking are more along the lines where this jacket will perform its best.
Fit: I’m 5’11” and 175 lbs, wearing the size medium.
The Good
- Classic, on-point Rab fit
- Top-notch materials and fabrics
- Form-fitting hood fits well and stays out of the way
- Low-profile, gusseted sleeve cuffs
- Lightweight and packable (about the size of a Nalgene bottle)
- Nice-sized front hand pockets (big enough for climbing skins)
- Great weather-resistance
- Stays stink-free after multiple adventures
The Bad
- Insulation gets overwhelmed after 15 minutes of high-output activity
- Once saturated, it’s cold
- Hard to find an ideal start/stop activity outside of alpine skiing
- Sleeves could be a tad longer
The Bottom Line: Rab Xenair Alpine Light Insulated Jacket
With the Xenair Alpine Light Insulated Jacket, you can expect lightweight warmth and weather protection for low-output activities. When pushed to its limits, you’ll be quick to overwhelm it. The key is reducing the duration of the “on” time to allow moisture to escape before it’s too late. Outside of that, the Xenair really is a beautifully-constructed jacket that’s made of top-notch materials.
Buy Now: Available from REI