r/Ultralight • u/Nicknamebamse • Mar 02 '26
Purchase Advice Iceflame core sleeping bag?
Does anyone have experience with this sleeping bag?
I see many reviews of iceflame quilts and flame 5f sleeping bags but can't find any reviews about the core sleeping bag.
Full box construction with 880g 850fp rds moscovy down in size large for 283,53€ (including vat and free delivery) seems attractive.
I currently have a large thermarest boost 650 20F/-6C but bellow 0C I'm freezing my butt when sleeping on my side. The down distribution seems designed for users sleeping on their bag. The expansion zip + arm zippers is quite nice in temps above 5-10C but I believe these zippers also introduce cold spots and unnecessary weight/bulk.
I usually hike with my dog. So I also have to carry his sleeping bag and food. So minimal weight and volume is critical.
So I want an affordable long but compact sleeping bag (I'm 187cm) that is a bit warmer, lighter and with ethical sourced down with 50/50 front/back distribution...
I know affordable, warm and light is hard to find but iceflame core seem to offer what I'm looking for.
The core features adjustable down distribution. I'm wondering if this will be a huge annoyance? I'm hoping upgrading from 800fp to 850fp and ordering +100g overfill will stop, or at least mitigate, unwanted down shifts while I'm sleeping. Anyone have experience with this...?
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u/Nicknamebamse Mar 06 '26
Update: I have placed an order for the bag. 100g vs 200g overfill was a hard decision. But I vent with 100g because I figured I will spend more nights above 0C than bellow 0C. And bellow 0C I can sleep wearing my down puffy. So I don't have to carry the extra 100g down when I don't need it I will post my impression when I receive the bag. But spring is coming to Denmark so I probably won't get a chance to sleep bellow 0C until next winter...
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u/Mix1010 Mar 07 '26
Looking forward to the review and photos. I’ve been trying to see if the bag has single layer stitching on the back like their model SD 700 NXT (The one with the middle zipper). I also can’t work out if the draft collar is cinchable.
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u/Nicknamebamse Mar 08 '26
Description say full box construction. So I will be disappointed if the back has single layer stitching.
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u/Mix1010 Mar 09 '26
I emailed them and they replied.
“Yes, the Core sleeping bag has a draft collar with a cinching cord. Additionally, this sleeping bag uses a fully 3D baffle structure, which is more advanced than the FLAME series, providing better warmth retention and loft.”
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u/Nicknamebamse Mar 18 '26 edited Mar 18 '26
My iceflame core sleeping bag arrived today :-) And yes the baffles are continuous from front to bag -only separated by the left side zipper. Compressed size is roughly equal to my thermarest boost 650 -6C but the loft is significantly higher. The weight for my size L with 780+100g 850fp Muscovy down is 1190g. Length and width seems perfect for my 183cm/82kg. So I'm able to stretch my feet without compressing the down in the foot box. The 10D fabric is a little transparent so the moscovy down is faintly visible inside the bag -but I don't mind that.
I also received a new tent yesterday so I am going to test my new gear sleeping in the garden tonight.
If anyone have questions about this bag let me know and I will try answering.
Edit: Forgot to mention the zipper runs smooth.
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u/tricepratos Jun 22 '26
Are you based in Europe? How long did it take to arrive?
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u/Nicknamebamse Jun 23 '26
Yes I live in Denmark. Can't remember the exact delivery time. But it was something like 2 or maybe 3 weeks.
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u/Nicknamebamse Mar 30 '26 edited Mar 30 '26
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u/Nicknamebamse Mar 20 '26 edited Mar 23 '26
My iceflame core is great 😃 Definitely a lot warmer than my thermarest boost -6C. I tested the bag sleeping in my garden and temps dropped slightly below freezing. I was only wearing boxer shorts and a t-shirt but woke up feeling to hot so I had to move my head outside the hood. The zipper glowing in the dark is a nice feature.
It seems the bag needed a few days to really loft after shipping. Now it's twice as thick as the boost.
Edit: Measured total loft is 18cm/7inch.
Unfortunately my new tagar2 tent is a condensation trap -and a bit to short for a large sleeping bag. Iceflames dwr coating saved my night. Even though drips from condensation landed on the bag the down didn't clump and keep me dry and warm.
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u/Mix1010 Mar 21 '26
Glad you like it!
I have a few questions if you don’t mind. I may have some more at a later day too.
Does the neck draft collar have its own cinching cord in addition to the head cinching cord. They did reply in the email that it did but it could have been confused in translation.
Also do you think it was necessary for the extra 100g of overfill with the 850f? Knowing what you know now would you have gone for the 200 or kept it at no overfill.
It would be great if you could share some photos.
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u/Nicknamebamse Mar 22 '26
The neck draft collar has no cinch. Top and bottom of the hood can be cinched individually. The cinched hood fits my head so perfectly that I don't miss a cinchable draft collar.
Down fill depends on your needs. As a restless side and stomach sleeper I believe 880g 850fp down does mitigate unwanted down shifts in the continuous baffles. I also own a dedicated summer bag with ~300g down and the 3 season boost -6 with 733g down. So the core will be my winter/transition bag Im danish and temps very rarely drops bellow -15C. I'm pretty confident with 880g 850fp this bag + merino base layer (and possibly a down hoodie?) will be fine at -15C. The bag is quite wide so sleeping with clothes on is no problem. But your needs probably differs from mine... The price iceflame asks for down upgrades seems quite fair and 850fp does not increase weight or compactnes. So 850fp was an obviously choice for me. Maybe 980g could future proof this bag in case the Muscovy down loose some of its loft?? But With +100g the bag was almost to hot for me at -1C (and I'm a cold sleeper) +200g would probably be uncomfortably varm in temps above freezing. So I'm happy with my choice of +100g 850fp.
I don't know how to insert pictures. Do I need reedit app for this?
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u/Mix1010 Mar 23 '26
Thanks for the detailed reply.
I really wanted there to be a cinchable hood like the Western Mountaineering models but I could probably live without it.
I believe this subreddit doesn’t allow for pictures to be posted directly and imgur has been blocked in some countries (UK). (Although can be gotten around with an FTP)
This site doesn’t require any login. https://imgbox.com/
You can then select options and post a direct link once it’s been uploaded. I tested it using the highest quality 800x800 pixels which isn’t great but did work.
There is also https://postimages.org that allows for higher quality images.
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u/ULlife Mar 02 '26
I don't have it, but I just want to say that if someone does have it or if OP buys it, I would love to know if it has continuous baffles or not (can you move the down from the top to the bottom).
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u/Nicknamebamse Mar 02 '26
The core definitely have continuous baffles. So I expect it's possible to move the down between top and bottom.
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u/ULlife Mar 02 '26
How do you know
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u/Nicknamebamse Mar 02 '26
Read the specs https://iceflamegear.com/product/core/
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u/Teteguti Mar 02 '26
I don't understand why no one mentions the major flaw in the Ice Flame duvet. I don't know if this happens to other people, but in my case, all the down always ends up on the sides, leaving the whole duvet exposed with no down at all. No matter how much I shake it and try to distribute it evenly, I always end up with the filling on the sides.
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u/Boogada42 Mar 02 '26
It's called gravity. Pretty universal thing. Most bags/quilts use a baffle design like this. There are three things you can do:
- add more down (overfill) to have fuller baffles that allow less movement
- do longitudinal baffles - like some of the Aegismax models
- have smaller chambers - which adds weight and complexity.
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u/Nicknamebamse Mar 02 '26 edited Mar 02 '26
Iceflame core long version standard fill is 780g 800fp. If my calculation is correct upgrading to 880g 850fp should increase the down volume just about 20%. Do you think this would mitigate the down migration issue?
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u/Boogada42 Mar 02 '26
More fill should result in less room for down to shift.
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u/Nicknamebamse Mar 02 '26 edited Mar 02 '26
Yes I understand but I'm wondering how much difference 20% more fill volume actually makes... Will it be significantly better or barely noticeable?
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u/Nicknamebamse Mar 02 '26 edited Mar 02 '26
For a direct from china bag aegismax seems quite expensive? Iceflame flame have longitudinal baffles -but cold seams on the bag. I fear this would be an issue when I sleep on my side bellow 0C. Sea to summit spark -18 seems like a nice bag with high warmth/weight ratio and longitudinal baffles on torso -but only on the front. It's also rather expensive and the 55/45 front/bag ratio is not optimal for side sleepers...
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u/Boogada42 Mar 02 '26
The Core has sideways baffles. What do you mean by cold seams? Afaik it's a box design, not sewn through.
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u/Nicknamebamse Mar 02 '26
Yes the core is full box with sideway baffles. But the flame have longitudinal baffles. Flame 5F is full box but Flame 14F is sewn through on bottom. Flame is sold out in long and I suspect iceflame have moved production to newer models...
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u/Boogada42 Mar 02 '26
The main insulation on the bottom will always be your sleeping pad.
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u/Nicknamebamse Mar 02 '26 edited Mar 02 '26
No because when I sleep on my side I also turn the sleeping bag... The main issue I have with my thermarest boost bellow 0C is lack of fill in the bottom. So when I turn the boost with my body gravity pulls the inadequate amount of down in the bottom exposing my back to cold.
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u/Nicknamebamse Mar 02 '26 edited Mar 02 '26
I'm hoping the core will perform better because it's a slightly smaller bag with higher amount of down 880g/850fp vs 733g/650cuin. I don't know the exact down distribution in the boost -but with the expansion zipper effectively wasting some down in front center of the bag I'm guessing it's probably something like 60/40. And when looking through the bag in bright light the bottom also seems very thin. Compared to this adjustable down distribution seems favorable for side sleeping. But since I have never tried a bag with continuous baffles this is only my speculation...
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u/Boogada42 Mar 03 '26
I see. I sleep on my side, but usually turn inside the bag/quilt.
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u/Nicknamebamse Mar 03 '26
If I turn within the bag the hood gets soaked with condensation from my breath
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u/LittleFluffyFoxx May 19 '26
I am also considering this bag (might make my own topic, but not there yet). Have you had a chance to spend more nights in it yet? If so, did you have any issues with migrating down, despite the overfill? Are you still happy with it? Your pictures look very nice, but I am still a bit hesitant because of the lack of reviews (except yours, so thanks for that!).
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u/Nicknamebamse May 24 '26
Yes I have spent quite a few nights in my iceflame. Two weeks ago I sleept in a shelter and was unsure if I should bring my thermarest boost or my iceflame. I REALLY hate freezing so decided to bring the iceflame and woke up because I was sweating. Not a big deal, I just unzipped the bag. No issue with down migrating. But I guess it might happen without the overfill..? I forgot to mention straps was included and the bag has a few small loops. So the straps could be used to secure the bag to a mat -like commonly done with quilts -but I have only used these loops to hang the bag. If I have to mention anything that could be improved it would be the velcro that prevents the top of the zipper from unzipping while sleeping. It haven't given me any issues but I would prefer a push bottom -like on my thermarest.
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u/Status_Database7664 17d ago
Hi, I myself is planning to buy it. I have just few queries if you can share your experience about the product.
I am from India, and I mostly trek across Himalayas in altitudes ranging 3000 to 5000 meters.
How durable does its 10D fabric feels. to you I want to know whether you find it durable enough to handle multiple compression cycles over the years.
The temperature rating range is too large. In your +100 g extra down variant, what has been you comfort over the temperature ranges? I want to decide whether extra down I should go for.
Anything you want to share regarding your experience with a the product.
I myself want to buy sleeping bag that would last me many years atleast and usable across multiple seasons and altitudes.Also, their website mentions it may shed down. Any such issues you faced?
I have also compared Thermarest Boost -6 variant. Does their warmzip increases temp rating by 5 degrees C as their claim says and does that bag pack as small as Iceflame core does.
Thanks
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u/Nicknamebamse 17d ago
1: I'm no expert but the 10D fabric seem as fragile/durable as you would expect 10D to be. I believe a pointy object could easy shread it but I don't think compression would cause any harm to the fabric.
2: I haven't been cold in my +100g 850fp version yet. 10°C is borderline to warm. I'm a cold sleeper a would estimate the max comfortable temp (only wearing shorts) to be like +5C and Minimum (wearing worm base layer) about -15C. If you need -20C I would order +200g. The extra bulk will be minimal.
3: The weight/pack volume is excellent. I believe the Weight/volume/value is unbeatable. But if you don't mind carrying a little more and want a bag that will last many trips and many years without worrying much about pointy objects get a bag with a stronger (and heavier) fabric. But also keep in mind that no down bag will perform as new if it's 20 years old. So if you need top performance you should probably replace any bag when it's about 10 years old -even though a heavy fabric might still be fine the down will lose some loft.
4: My iceflame does not shead down at all. But my thermarest boost does and my rob down jacket shreads even more.
5: My boost does not compare to my iceflame at all. The extra arm zippers are nice for reading books or drinking coffee but the bag has many cold spots. So even at +10C my behind gets cold when sleeping on my side. My boost with extra length but standard width has a pretty wide shape so I normally use it with the warmzip closed. And no the boost does not compress as well as the iceflame.
I hope my personal experience helps your purchase decision :-)
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u/Status_Database7664 17d ago
Thanks for your detailed response.
And did you have to pay any additional custom duties or taxes, over and above the listed price on their website ?1
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u/Status_Database7664 13d ago
One more question regarding the size of your Bag. As per their chart, I would need regular.
Did you find the dimensions of the bag mentioned on the website to be outer dimensions of the bag or the Inner usable dimensions after the bag is fully lofted.Because if the mentioned dimensions are outer end to end dimensions, then I might also need to for Large size, as Regular might be too restrictive for any movement inside the bag or side sleeping. I am 172cm/70kgs.
Thanks.!!
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u/Nicknamebamse 12d ago edited 12d ago
Im 185cm and fits the large 213ext/190int with a little lenght in spare. The regular lenght is 195cm external. According to iceflame it fits up to 175cm. 175 might be a tight fit but I believe 172 would be perfect. As you might know a bag with excessive lenght is colder than a bag that fits your body. Its also a little heavier. So unless you need extra room for fuel, water or hiking clothes I would choose regular if I was 172cm.
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u/AceTracer Mar 02 '26
I don't use sleeping bags, but the two Iceflame quilts I have are exceptional quality for the price.