Review: Himali Accelerator Down Jacket

Down Jacket
Himali Accelerator Down Jacket
$330, 12.5 oz./354g (men’s medium)
Sizes: men’s S-XXL, women’s XS-XL

On cool mornings and windy evenings in the low 40s Fahrenheit (4-6° C) in campsites while backpacking the Skyline Trail in Jasper National Park and the Nigel, Cataract, and Cline Passes Route in the White Goat Wilderness in the Canadian Rockies in August, my Himali Accelerator Down Jacket kept me perfectly warm over just one or two base layers. By many measures, this midweight puffy hits the target for three-season mountain adventures in its balance of weight, packability, warmth, materials, water resistance, and features—all at a competitive price for a high-quality down jacket.

In fact, it’s tempting to call the Accelerator the Goldilocks of down jackets, because it seems so ideal for camping in the mountains in the typically cool weather of summer and fall, or spring and fall in the desert Southwest: It’s not so thin and lightweight that it’s never quite warm enough for many people, but also not overly warm, which would make it unnecessarily heavier and bulkier.

For a lot of humans whose personal metabolism falls somewhere between the people who are warm enough in an ultralight down jacket and the people who need the fattest puffy jacket even in summer, the Accelerator may feel just right.

Hi, I’m Michael Lanza, creator of The Big Outside. Click here to sign up for my FREE email newsletter. Join The Big Outside to get full access to all of my blog’s stories. Click here for my e-guides to classic backpacking trips. Click here to learn how I can help you plan your next trip.

The Himali Accelerator Down Jacket.
The Himali Accelerator Down Jacket in the White Goat Wilderness, Canadian Rockies.

At 12.5 oz./354g (men’s medium) and packing down to a bit larger than a liter bottle, the Accelerator is a middleweight among three-season insulated jackets—in between models weighing 10 ounces/283.5 grams or less and those weighing up to around one pound/453.6 grams. (Insulated jackets over a pound are generally designed for winter—or not for the backcountry.) That fact and its combination of materials and design features give it multiple advantages over many competitors.

Stuffed with four ounces of RDS-certified, 850-fill, water-resistant HyperDry down, the Accelerator delivers a very high warmth-to-weight ratio that competes with the few very best down jackets at this or any weight. High-quality down creates more space between feathers, increasing heat-trapping efficiency, which translates to more warmth per ounce of jacket. And very few down jackets have down with a higher rating than 850-fill—with most of those being lighter and/or significantly more expensive.

Find your next adventure in your Inbox. Sign up for my FREE email newsletter now.

The Himali Accelerator Down Jacket.
The Himali Accelerator Down Jacket.

To prevent moisture from your body compromising the loft of the down feathers, and consequently, the jacket’s warmth—especially if circumstances require you to wear this jacket when on the move—Himali placed Primaloft Gold synthetic insulation in high-moisture areas like the underarms and at the chin, for its ability to trap heat when damp. That’s a rare design feature in down jackets that you may reap the benefits of when you most need it.

The 20-denier Pertex Quantum ripstop nylon shell with a DWR (durable, water-resistant coating) and water-expanding thread also help keep moisture out. The lightweight fabric compares with many down jackets made for the backcountry: Sufficiently durable for normal use but exercise all due caution with it.

That combination of mapped synthetic insulation and the water-resistant HyperDry down and shell fabric give the Accelerator a large performance advantage over standard down jackets in persistently wet weather and situations where you need to wear this jacket before you’ve stopped moving for the day—and want it to remain warm once you’ve reached camp.

The one-hand adjustable, under-the-helmet hood closes snugly around my head, creating a seal around my entire face with the zipper pulled up to my chin—the kind of fit that keeps cold air off your neck, which insulated jackets with a looser fit and inferior hood do not achieve. That fit means the hood turns with your head (saving you from the annoying experience of the hood covering one eye).

Anyone seeking an insulated jacket for year-round backcountry use might find the Accelerator delivers the right amount of warmth for those short rest breaks when you need to throw on another layer and for moving in very cold conditions, especially downhill (although it is not warm enough to function as your primary insulation when camping or for an unexpected, emergency overnight bivy). The water-resistant down would help prevent moisture buildup from perspiration or precipitation—and you’d wear a shell over it in any significant precip—and its warmth-to-weight ratio would exceed that of almost any synthetic insulated jacket.

I’ve helped many readers plan unforgettable backpacking and hiking trips.
Want my help with yours? Click here now.

The Himali Accelerator Down Jacket stuffed.
The Himali Accelerator Down Jacket stuffed.

The excellent fit allows layering it over a couple of base layers and possibly one light insulation layer for some people: With a 38-inch chest and 30-inch waist, I was able to wear a light fleece hoodie underneath the men’s medium Accelerator. Still, there isn’t an excessive amount of space when I wear it only over one or two base layers, so thermal efficiency is very good.

Plus, the front zipper closes comfortably snugly at my chin (with a soft, fleece chin guard), keeping cold air off my neck, and the adjustable hem and stretch cuffs seal in heat. Good articulation in the sleeves and shoulders prevents the jacket from bunching or riding up when moving around or raising your arms overhead. It also comes in five men’s and women’s sizes.

The two warm, zippered hand pockets are spacious enough to fit a pair of warm gloves in either of them and the jacket packs into a smartly integrated stuff sack in the left hand pocket. The one internal zippered pocket is larger than a smartphone.

Himali also offers a non-hooded version of the Accelerator Down Jacket ($310).

The Verdict

With a very high warmth-to-weight ratio, good water resistance and packability, a great fit, and what may be a perfect degree of warmth balanced with a modest weight, the Himali Accelerator Down Jacket just may be the ideal puffy for many backpackers, climbers, and other adventurers.


You can support my work on this blog, at no cost to you, by clicking any of these affiliate links to purchase a men’s hooded Himali Accelerator Down Jacket at, a women’s hooded Himali Accelerator Down Jacket at, a men’s non-hooded Himali Accelerator Down Jacket at, or a women’s non-hooded Himali Accelerator Down Jacket at

Readers of The Big Outside get an exclusive 10 percent off their Himali purchase by using the discount code THEBIGOUTSIDE.

See “The 10 Best Down Jackets” and all reviews of insulated jackets and outdoor apparel at The Big Outside.

NOTE: I tested gear for Backpacker Magazine for 20 years. At The Big Outside, I review only what I consider the best outdoor gear and apparel. See categorized menus of all of my gear reviews at The Big Outside.

—Michael Lanza

The Big Outside helps you find the best adventures.
Join now for full access to ALL stories and get a free e-guide and member gear discounts!


The Best Hike in Bryce Canyon National park

Review: BioLite Firepit+ Portable Backyard Fire Pit and Grill


Leave a Comment