With 850 fill power down and lots of it, the Flame is very warm, light and lofty. We love this bag and think it's an excellent choice for lightweight backpacking.
Performance Comparison
The S2S Flame 15 is super warm. At low elevation in the summer it was too warm some evenings.
Warmth
This bag is EN-rated to 15 degrees Fahrenheit, and we think that rating is spot-on. The Flame has almost 23 ounces of high quality 850 fill power down that is super lofty and fluffs this bag right up. It is neck and neck with the other top contenders in this review in this rating metric.
The Sea to Summit Flame - Women's is one of the warmest and loftiest bags we tested.
The Flame also has huge fluffy neck baffles around the front and back to stop any pesky drafts from coming in down your neck. Sea to Summit claims the Flame has "down chambers filled using body-mapping to maximize warmth for a woman's physiology." We're not sure what this means, but half of its baffles are sewn vertically while the lower ones are horizontal, the jury is out whether this makes a difference in warmth.
You can stretch this warm bag into the winter months paired with a warm sleeping pad and tent.
Weight
Weighing in at 1.95 pounds this bag is not crazy lightweight, but it's not heavy either, it's just a smidge heavier than the lightest models we tested. However, those bags are not as warm as the Flame, which makes up for the few extra ounces. The shell materials appear to be very light and delicate as they are translucent and you can see the down feathers and clusters right through the materials.
Two of our lighter additions this round, the Sea to Summit Flame and the Nemo Aya. Both products are focused on weight savings.
Comfort
We were pleasantly surprised by how comfortable the Flame is. It is a simple mummy shape that is roomy enough to move around a bit, and fit our 5'5 tester very well. It is so light and fluffy; it feels very cozy.
Packed Size
The Flame comes with a great compression sack that will pack this bag down super small. This bag takes a bit more effort to get into its compression sack as the materials seem to have a waterproof coating that takes effort to get the air out of when compressing it down.
The Flame (left) and the Aya in their included compression sacks.
Features
This bag has few bells and whistles, which we like! The high-quality materials and streamlined design are a simple, weight-saving feature. We do wish it had a small stash pocket for those essentials like a headlamp or earplugs we want during the night. We also noticed that the zipper is not particularly high-quality and prefer ones with anti-snag pulls. The Flame comes with a strange rectangle-shaped "case" for storage. We do not like it at all. It is difficult to get the bag back in the case, and it leaves the Flame partially compressed during storing, which is less than desirable.
The Sea to Summit Flame has very high quality down fill and it's shell materials are lightweight and translucent so you can see the down through it.
The Sea to Summit Flame is a lightweight choice for long backpacking trips.
Value
Here is this product's one Achilles heel - it's the most expensive bag we tested. This aspect is the one reason we would hesitate to buy it.
Conclusion
We love this bag and commend Sea to Summit for putting out such a technical product for women. We wish all manufacturers would put this much intention into new products for women. The Flame is light, super warm and lofty, and very comfortable. Now if we could just work on getting that price tag down a bit, we could wholeheartedly recommend it.
The women's Flame has a very warm hood and interior draft collar.
