Head-to-head · Best 0 Degree Sleeping Bags

Feathered Friends Ibis ES 0 vs Sea to Summit Spark 0F

Which is the better buy? Side-by-side on rating, price, strengths, and watch-outs — with the published ratings we averaged to get there.

The short answer

Feathered Friends Ibis ES 0 comes out ahead by a narrow margin (4.6 vs 4.4). The gap is mostly about Winter campers in cold, wet, or condensation-prone conditions who want a conservatively rated bag and will pay top dollar for a waterproof shell. — read the strengths below before deciding.

Higher ratedRanked #2 in Best 0 Degree Sleeping Bags

Feathered Friends Ibis ES 0

4.6

$859as of Jun 8

The Ibis ES 0 pairs 900+ fill power goose down with a waterproof-breathable Pertex Shield EX shell, making it the bag to beat for cold, damp winter conditions. Feathered Friends rates conservatively, so its 0°F is closer to a true comfort rating than a survival limit. It is the widest of the brand's zero-degree bags, but it is also among the heaviest here at 3 lb 2 oz.

Strengths

— 900+ fill power goose down, the highest-loft insulation in this group
— Waterproof-breathable Pertex Shield EX shell handles condensation and damp tents
— Conservative 0°F rating means real-world comfort at the stated temperature

Watch-outs

— Heavy for a 0°F down bag at 3 lb 2.4 oz for the regular
— List price of $859 puts it at the top of the category
— Waterproof shell adds weight and slightly less breathability than open nylon

$859 · Buy at featheredfriends.com Full review →

Ranked #4 in Best 0 Degree Sleeping Bags

Sea to Summit Spark 0F

4.4

$349as of Jun 8

The Spark 0F is the ultralight of this group, packing a genuine 0°F-rated bag into about 2 lb 7 oz and a sub-10-liter stuff size. It uses 850+ fill Ultra-Dry down and reviewers find its temperature rating accurate. The trade-offs are a snug, less-forgiving cut and a thin shell that offers little wet-weather protection, plus a steep price for the warmth.

Strengths

— Among the lightest 0°F down bags at roughly 2 lb 7 oz
— Sub-10-liter packed size, the most compressible bag here
— 850+ fill power Ultra-Dry treated goose down resists moisture

Watch-outs

— Snug ultralight cut is less forgiving than the Kodiak or Ibis
— Thin shell offers little wet-weather protection
— Pricey at roughly $649-$679 for the warmth delivered

$349 · Buy at seatosummit.com Full review →

How they stack up

Feathered Friends Ibis ES 0

The highest-loft and most weather-resistant bag here thanks to 900+ fill and a Pertex Shield EX shell, rivaling the Western Mountaineering Kodiak MF for warmth but heavier than it, the Mountain Hardwear Phantom 0, the Therm-a-Rest Parsec 0F and the Sea to Summit Spark 0F.

Sea to Summit Spark 0F

The lightest and most compressible bag here, undercutting the Therm-a-Rest Parsec 0F on weight and packed size and far lighter than the Western Mountaineering Kodiak MF, Feathered Friends Ibis ES 0 and Mountain Hardwear Phantom 0, but with a snugger cut and a thin, less weatherproof shell.

Specs side-by-side

Spec	Feathered Friends Ibis ES 0	Sea to Summit Spark 0F
Temperature Rating	0°F (-17.7°C) comfort	0°F limit / 14°F comfort
Fill Power	900+ goose down	850+ Ultra-Dry goose down
Fill Weight	1 lb 15.2 oz (884 g)	29.6 oz (840 g)
Total Weight	3 lb 2.4 oz (1429 g)	2 lb 7 oz (1113 g)
Shell	Pertex Shield EX waterproof-breathable	Ultralight nylon
Shoulder Girth	59 in	—
Packed Size	17 L	9.9 L
Origin	Made in Seattle, USA	—
Zipper	—	Full-length YKK with draft tube
Cut	—	Snug ultralight mummy

← See the full ranking of best 0 degree sleeping bags