Western Mountaineering UltraLite 20 vs Feathered Friends Hummingbird UL 20
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In short: The Feathered Friends Hummingbird UL 20 costs $41 less; the Feathered Friends Hummingbird UL 20 saves 5.1 oz.
| Spec | Western Mountaineering UltraLite 20 | Feathered Friends Hummingbird UL 20 |
|---|---|---|
| Approx. price | ~$680 | ~$639 |
| ISO comfort | not published | not published |
| ISO limit | not published | not published |
| Rating on the label | 20 °F | 20 °F |
| Honesty gap | — | — |
| Rating standard | manufacturer | manufacturer |
| Weight | 1 lb 13 oz | 1 lb 7.9 oz |
| Warmth per ounce | — | — |
| Fill | 850 fill power down | 950 fill power down |
| Fill weight | 16 oz | 14 oz |
| Loft budget | 13.6k in³ | 13.3k in³ |
| Shape | mummy | mummy |
| Shoulder girth | 59 in | 57 in |
| Zipper | full | full |
| Shell fabric | 12D ExtremeLite ripstop nylon | Pertex Quantum Pro 7D × 30D ripstop |
| Hydrophobic down | No | No |
| Packed size | 7 × 13 in | 9 L |
Shaded cells mark the row where one has a measurable advantage. Weight, thickness, girth and shape are left unshaded on purpose: heavier is sometimes tougher, wider is sometimes warmer, and calling a winner on those would be an opinion dressed as a measurement.
What each one does well, and costs you
Western Mountaineering UltraLite 20
- Publishes measured loft in inches and exact down weight per size, which is a more checkable claim than a temperature number.
- Continuous horizontal baffles let the down be redistributed by hand — more down on top when it's cold, spread out when it isn't.
- 16 ounces of 850-fill down in a 29-ounce bag, with a 59-inch shoulder girth that is roomy for the weight.
- Built in San Jose, and Western Mountaineering will re-loft and repair bags decades old.
- 12-denier ExtremeLite shell is unusually high thread count for its weight, which is where the durability reputation comes from.
- No ISO or EN rating at all; the 20 °F figure has only the company's reputation behind it.
- $680 in the middle size, the most expensive standard-width 20-degree bag here.
- The down is untreated — no hydrophobic finish — which is a deliberate choice but a real limitation in a wet tent.
- Three lengths and a single girth: no wide option for a broad-shouldered sleeper.
Feathered Friends Hummingbird UL 20
- 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.
- 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.