Feathered Friends
Feathered Friends Hummingbird UL 20
No citable owner-review average published for this one, so no stars.
Twenty-three point nine ounces for a hooded, full-zip 20-degree bag with 950-fill down — the lightest bag of its kind in this catalogue by about five ounces. Feathered Friends gets there with a 7-denier-by-30-denier Pertex Quantum Pro shell, which is a waterproof-breathable fabric rather than a simple ripstop, and by trimming the shoulder girth to 57 inches. That last number is the thing to check before buying: this is a close-fitting bag, and a broad sleeper will compress the down against the shell and be cold in it.
Label against lab
No ISO or EN rating is published for this one — the 20 °F is Feathered Friends’s own figure, with no lab test behind it. Where a maker publishes loft or fill weight instead, those are the numbers worth comparing. What the standards measure
At that temperature the pairing table wants at least an R 4 pad underneath it.
Size run
One product, 2 sizes. The headline numbers on this page describe the Regular.
| Size | Weight | Approx. price | Length | Shoulder girth |
|---|---|---|---|---|
| Regular | 1 lb 7.9 oz | ~$639 | — | 57 in |
| Long | 1 lb 9.1 oz | ~$659 | — | 57 in |
Specifications
Highlights
Features
- RDS down
- Draft collar
- Full-length zipper
- Made in USA
What it does well
- 23.9 ounces for a hooded, full-zip 20-degree bag is the lightest in this catalogue by a clear margin.
- 950+ fill-power down, the highest grade here outside the NEMO Pulse's 1000.
- The Pertex Quantum Pro shell is genuinely water-resistant rather than just DWR-treated, which matters on a bag with this little fabric.
- Published girth at shoulder, elbow, hip and footbox, and exact fill weights per length.
What it costs you
- 57-inch shoulder girth is the narrowest of the premium bags here — measure before you buy.
- $639 for the Regular.
- No ISO or EN figure.
- 7-denier shell fabric on the face; this is a careful-owner bag.
- Untreated down inside a very thin shell.
Those two lists are drawn from Feathered Friends’s published specifications and from reviews that measured them. They are not owner sentiment — anything owners said appears under its own heading below.
What owners say
Distilled from owner discussions and long-term published reviews, not from anything measured here.
Owner sentiment about the Hummingbird is warm in both senses. People describe years of ownership, unusual enthusiasm about getting into it, and real warmth for the weight. That is what a 950-fill bag at under a pound and a half is supposed to deliver, and by these accounts it does.
The one substantive criticism is oddly specific and worth knowing before buying: the zipper. An owner returned theirs and bought a competitor instead because the chunky proprietary zip has no terminal garage, so at full zip with the hood cinched down there is exposed hard plastic against the face. They were explicit that the rest of the build quality was excellent — it is a design detail, not a manufacturing one.
The other limit is the cut. This is the narrowest of the premium bags, and the weight comes partly from that.
What owners like
- Owners describe three years of ownership and still getting a little giddy climbing into it, which is not how people usually talk about sleeping bags.
- The warmth reports are strong — owners call it insanely warm for its weight.
- Build quality gets praised even by people who returned theirs, which is a useful separation of quality from design.
- Owners pair it with the maker's quilt in the same line and treat the whole range as high quality.
Common complaints
- The proprietary zipper is a real complaint: one owner returned the bag because at full zip and full hood cinch there is a rough piece of plastic against the face, with no terminal garage covering it.
- It is expensive even by premium standards.
- The narrow cut is the tradeoff for the weight, and it will not suit a broad sleeper.
- No lab rating, so the 20 is the maker's own number.
Questions owners ask
What is the problem with the zipper?
Is it warm for its weight?
Is the cut too narrow?
Feathered Friends Hummingbird UL 20, head to head
Others in the same band
More from Feathered Friends →
Feathered Friends
Feathered Friends Swallow YF 20
Feathered Friends sew every bag in Seattle and publish girth at four points — shoulder, elbow, hip and footbox — which tells you more about whether a bag will fit than any temperature rating can. The Swallow is their three-season workhorse: 900-fill-power Muscovy down, 16.8 ounces of it, in a 59-inch-shoulder mummy that weighs 29.2 ounces. Like Western Mountaineering they publish no ISO figure, and like Western Mountaineering they have a forty-year record that people buy on instead.
Best for: Three-season backpacking where fit matters as much as warmth
Full spec sheet
Western Mountaineering
Western Mountaineering UltraLite 20
Western Mountaineering has been building bags in San Jose for fifty years and has never published an EN or ISO rating for any of them — the 20 °F on the UltraLite is the company's own number, and its reputation rests on that number having been accurate for two generations of backpackers. What it does publish is the physics: 5.5 inches of measured loft, 16 ounces of 850-fill goose down, 59 inches of shoulder girth and a 12-denier shell, for a total of 29 ounces. Continuous horizontal baffles let you shake the down to the top on a cold night or to the sides on a warm one, which is a feature almost nobody else offers and which more than compensates for the missing zip vent.
Best for: Buyers who plan to own one bag for twenty years
Full spec sheet
Western Mountaineering
Western Mountaineering AlpinLite 20
The UltraLite cut wider: same 20-degree rating, same 5.5 inches of loft, five more inches of shoulder girth and three more ounces of down to fill the extra space. Two ounces of total weight is the whole cost of the upgrade, and for anyone who has felt pinned in an UltraLite it is the obvious choice. The 7'0" length is the only bag in this catalogue that fits someone genuinely tall without compromise.
Best for: Broad-shouldered or very tall sleepers who want a proper down bag
Full spec sheet