Kelty
Cosmic Synthetic 0 Degree
Best reliable warmth for budget conscious cold weather campers.
Designed for three-season backpacking, this mummy bag balances thermal efficiency with a budget-friendly price point. It utilizes synthetic insulation to maintain loft and warmth even in damp conditions, ensuring reliable performance on the trail. The interior features a spacious footbox that allows for natural movement, while the soft-touch fabrics provide a comfortable sleeping environment. A dedicated stash pocket keeps small essentials secure and accessible throughout the night. This option is an ideal choice for hikers seeking a dependable, low-maintenance solution for cold-weather excursions without the premium cost associated with down alternatives.
$139.95
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Kelty Cosmic Synthetic 0 Degree Sleeping Bag
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Kelty Cosmic Down 20
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Cosmic Synthetic 40 Degree
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Cosmic Synthetic 20
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Owner Satisfaction
4.5
/ 5
Category Rank
1010
/ 2020
#1010 in Sleeping Bags
Price vs Category Average
-16%
Below average
ISO Comfort Temp Rating
18
/ °F
Who it's for
- Campers needing reliable warmth in freezing conditions.
- Outdoor enthusiasts facing unpredictable or humid weather.
- Budget-conscious adventurers seeking a high-performance sleeping bag.
Who should skip it
- Backpackers prioritizing ultralight gear and minimal pack volume.
- Hikers with limited pack space or those who value compact gear.
- Users seeking maximum longevity and consistent performance over many years.
Performance breakdown
Thermal Efficiency
CirroLoft insulation provides reliable warmth even when conditions turn damp.
Weight-to-Warmth Ratio
Synthetic fill adds significant bulk compared to premium down alternatives.
Footbox Comfort
Spacious design allows for natural movement without restricting toe space.
Moisture Management
PFC-free DWR coating effectively sheds light moisture and condensation.
Fabric Durability
Taffeta shell balances a soft hand-feel with rugged trail resilience.
Packability
Substantial fill weight requires considerable space in your backpacking pack.
Key Specs
ISO Comfort Temp Rating
18°F
ISO Limit Temp Rating
5°F
Max User Height
72 inches
Length
78 inches
Shoulder Width
31 inches
Total Weight
4.67 lbs
Fill Weight
55 oz
Insulation
CirroLoft synthetic
Know before you buy
While it is marketed as a 0-degree bag, the ISO ratings provide a more precise look at performance. It has an ISO Comfort rating of 18°F and an ISO Limit rating of 5°F, meaning it is best suited for late autumn or early spring backpacking trips rather than deep winter conditions.
The CirroLoft synthetic insulation is designed to retain its loft and warmth even when damp, which is a significant advantage over down insulation in humid or rainy environments. It is a reliable, low-maintenance choice for hikers who prioritize durability and moisture resistance over packability.
Yes, this bag is designed for users up to 72 inches (6 feet) tall. With an overall length of 78 inches, it provides enough room for a comfortable fit without feeling overly restrictive.
The Natural-fit footbox is specifically shaped to allow for natural toe movement and foot positioning. While it is a mummy bag, the design is intended to prevent that cramped, pinned-in feeling often found in more tapered models.
The PFC-Free DWR (Durable Water Repellent) coating helps the shell fabric shed light moisture and condensation. It is an environmentally conscious choice that maintains the bag's water resistance without using harmful perfluorinated chemicals.
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$140