Kelty
Cosmic Down 20 Sleeping Bag
$189.95Cheaper
Released 2024
Best Sleeping Bags · head-to-head
Cosmic Down 20 Sleeping Bag vs UltraLite Sleeping Bag
A sourced, side-by-side comparison. Cosmic Down 20 Sleeping Bag is cheaper at $189.95. Every spec and price links to its source.
Western Mountaineering
UltraLite Sleeping Bag
$660
Which is better: the Cosmic Down 20 Sleeping Bag or UltraLite Sleeping Bag?
The UltraLite Sleeping Bag wins 1 of the 1 specs we compare head to head; the other wins 0. The Cosmic Down 20 Sleeping Bag is the cheaper at $189.95. Get the UltraLite Sleeping Bag for the stronger spec sheet, the Cosmic Down 20 Sleeping Bag to spend less.
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Full spec sheet
✓ marks the stronger figure where "more" — or "less", for price and weight — is unambiguously better.
| Spec | Cosmic Down 20 Sleeping Bag | UltraLite Sleeping Bag |
|---|---|---|
| US price | $189.95 MSRP, regular size, per kelty.com | $660 |
| Brand | Kelty | Western Mountaineering |
| Released | 2024 | — |
| Temperature rating f | 20 | 20 |
| Insulation type | down | down |
| Fill power | 550 | 850 |
| Shape | semi-rectangular | mummy |
| Packed weight (lb) | 2.44 | 1.81 |
| Packed size | 8 x 13 in | 7 x 13 in |
| Zipper side | right | left or right |
| Product note | 550-fill DriDown; ISO comfort 31F, lower limit 21F; regular weight 2 lb 7 oz | 850+ FP ethically-sourced premium goose down; USA made; full-length #5 YKK zipper; 6'0" version weighs 1 lb 13 oz |
Sources — Cosmic Down 20 Sleeping Bag: kelty.com (verified 2026-06-20). UltraLite Sleeping Bag: westernmountaineering.com (verified 2026-06-20).
What's the difference between the Cosmic Down 20 Sleeping Bag and UltraLite Sleeping Bag?
Where the two actually differ on the specs we track (6 of 8). Matching specs are omitted.
- Fill power: Cosmic Down 20 Sleeping Bag 550 vs UltraLite Sleeping Bag 850
- Shape: Cosmic Down 20 Sleeping Bag semi-rectangular vs UltraLite Sleeping Bag mummy
- Packed weight (lb): Cosmic Down 20 Sleeping Bag 2.44 vs UltraLite Sleeping Bag 1.81
- Packed size: Cosmic Down 20 Sleeping Bag 8 x 13 in vs UltraLite Sleeping Bag 7 x 13 in
- Zipper side: Cosmic Down 20 Sleeping Bag right vs UltraLite Sleeping Bag left or right
- Product note: Cosmic Down 20 Sleeping Bag 550-fill DriDown; ISO comfort 31F, lower limit 21F; regular weight 2 lb 7 oz vs UltraLite Sleeping Bag 850+ FP ethically-sourced premium goose down; USA made; full-length #5 YKK zipper; 6'0" version weighs 1 lb 13 oz
What reviewers say
Sourced tester consensus for each — the "what people who used it think" layer, not just specs.
Cosmic Down 20 Sleeping Bag
Two whitelisted hands-on testers (CleverHiker, Switchback Travel) reviewed the Kelty Cosmic Down 20 and both call it a strong-value budget 3-season down bag. Both praise its warmth-to-weight ratio, buttery-soft lining, and low price, and both flag it as heavy and bulky for a backpacking-specific bag while noting the large gap between the women's and unisex versions. CleverHiker's tester observed comfortable warmth to 30F against the 20F spec. All six quotes and the one measured value were verified as literal substrings of the fetched source text. (2 sourced reviews, 2 lab-tested.)
Praised: Excellent warmth-to-weight ratio and cozy, buttery-soft lining; Strong value / affordable for a down bag; Draft collar/tubes and adjustable hood seal in heat well for 3-season use.
Flagged: Heavy and bulky for a backpacking-specific down bag; Large price and weight gap between women's and unisex versions; Narrow mummy fit limits room to spread out.
UltraLite Sleeping Bag
No sourced tester review yet.