You can feel the difference
I'm not sure why some people feel that this liner is not warm. I purchased one for both my wife and myself and so far we love them.
The first night we used them, we stayed in a cabin that had beds but no linens. We used the liners as a sheet with the sleeping bags as blankets and we were totally comfortable, despit turning off the heat in the cabin with temps in the low 30's overnight. In fact, most of the night we were overly warm.
The next night we were on the trail and used them inside a tent after a day of backpacking. It was in the mid 70's during the day and we were covered in bug spray, sweat, and sunblock. Normally I hate sliding into my sleeping bag and sticking to it after a day on the trail. Having the liner made me much, much more comfortable since I wasn't sticking to the sleeping bag with every inch of exposed skin.
Over night the temp dropped down to about 40, and we had left the rain fly open for ventilation. Despite the low temps we stayed warm with the sleeping bags partially zipped. I was wearing summer hiking pants, a wicking short sleeved shirt, and socks while wrapped in a 20 degree bag. The pad was on an Exped UL 7. Most of the night I was overly warm, but I did cool off towards the morning and finally zipped the bag up.
After returning home we noticed the smell of the bug spray, sunblock and other hiking funk were on the liner, but not in the expensive sleeping bags. The liner was easily washable with the rest of our clothes and hung up to air dry.
For those who reviewed the liner used out of the sleeping bag and felt discomfort, the manufacturer states clearly on the web site that the liner is not designed for that use since it readily flows air as part of the design to keep you comfortable inside the sleeping bag without sweating. Therefore, using it on your couch under a running ceiling fan is not really a good test. If you don't think it adds warmth, turn off the fans and the air for a couple of minutes, and you will quickly feel the extra warmth.
Overall, we both feel that this was worth the additional money spent. We have not tried other liners but it's hard to imagine something else this light doing the job as well, although I'm not sure 15 degrees of addes warmth would accurate, since it's probably lower than that. We do value our money, and spend lots of time researching our gear before we purchase something with our hard-earned dollars. We hope others find this review useful and have the same experience that we did.
This review might be a bit odd for some people, but I'm guessing some will get it. I don't like the feel of most sleeping bags against my skin. Never been a big fan of nylon. Of course it is what is and I love backpacking. I use this liner even when I don't need extra warmth just cause I love the way it feels. The extra warmth is a very nice bonus. It definitely adds warmth I just don't know how much extra warmth it adds I've never tested one night, one night without.
I can say that right after I bought this I was messing with it in my truck whilest driving. (Ya, I know 10 and 2.) I had it pulled out of the bag and I put hood up over my head. Even though my cab was a comfortable temperature, my head was sweating within about 5 minutes of having wearing it.
I can also add that on my most recent hike I was of course using this liner in my bag. During the night the liner came down around my waist only covering lower section I felt a slight chill around my chest and and arms. I woke up and pulled the liner back up all the way and was back to be being nice and warm in no time.
So in short I'd buy this again. I'm not sure if really gets as many degrees as the advertisement says, but it does get the job done.
ABSOLUTELY EXELENT !!!
OK so I got this "liner" bag as a sleeping bag when I took my good bag to cleaners and cause they messed up I was not able to get it back in time for my trip. As it was not going to be too cold I guessed that this along with my layers would suffice for the weather. I did not want to spend a grip getting another full-on bag (assuming I would eventually get mine back from the cleaners, but that is a different thing) so I decided to take a chance on this one.
I AM so satisfied and happy I did. I don't think I will ever take a full bag on a summer trip again. This kept me warm and was light and even more importantly very compact. It performed well on the initial trip and a few others so far. I have used it in the wind and while it is not designed as a windshield with a slip on cover I made from a couple of trash bags I got a super-compact lightweight bag and groundcover all in one.
This thing has held up great so far and after very close inspection I have found no defects after multiple uses, and I am a rough sleeper.
When I was purchasing my new sleeping bag the sales associate recommended this to add warmth and to help extend the life of my bag. At first I thought they were just trying to sell me add ons that I really didn't need and I was hesitant at first but after carrying it around the store for a while I figured I could try it out and always return it. The material of the liner is super thin so I was skeptical on its ability make my bag warmer. I'm SO glad I purchased it! I was grateful to have this liner with me on cold nights. I can really tell the difference and agree it probably adds 10 degrees of warmth which is great for a cold sleeper like me! I have even used the liner as a super light sleeping bag on warm summer nights. It packs a lot of warmth in that small package!
i've only had one opportunity to use this since i just purchased it, but so far, so good. we camped in 20 degree weather and my husband had to shed his after getting too warm (we also have 0 degree bags, but they are ~15 years old) so i doubled up and had the best camp sleep ever. he would likely leave a less glowing review since he is a human radiator and also like to turn cartwheels in his sleep and found the liner a bit too confining. typically, we zip our bags together which gives him a bit more room to kick me in his sleep, however, since these are super light, there are no zippers to combine them so he was additionally confined to his own sleeping bag (probably another reason i slept so good!). short story long - i loved the liner, but he would probably have a different story.
The liner typically seems to add about 10-15 degrees to a sleeping bag rating. I'm in the Marmot eco-pro 15 degree bag, which has an EN rating of about 29F, and it has allowed me to use the bag on winter trips down to 15 degrees comfortably while wearing light long johns. I'm a warm sleeper. The liner is flexible, so it moves with you when you sleep and doesn't feel constricting. Like most liners it takes away the damp feeling in a bag and saves it from extra wear. I'd give it a 5 if it were made to absorb less smell, as a week in it without a wash/rinse allows one to smell the self quite well. All in all, great product, and on the lighter end for this type of item and amount of warmth provided. Used camping in Wyoming, Montana, Idaho, South and North Dakota, West Virginia, and Pennsylvania.
Favorite camping item I've purchased
This is easily the best item I've purchased for backpacking.
It's so versatile. I can use it in Summer when it's 75F+ on it's own without another sleeping bag or blanket. Or I can add it to my winter bag on nights when it's 0F and not feel cold at all.
It's very lightweight. I can use it with my lightweight bag at 40F and feel cozy and warm.
It is incredibly comfortable and soft. One of the other reviews said she brings it on the plane... that's a brilliant use as plane blankets aren't always available or comfortable for that matter.
I haven't had to wash it so I can't comment on the wear or lack there of after washing, but I can say that it is pretty durable and it has made it on four of five weekend adventures with me so far.
Versitile Liner, good on it's own
Purchased this liner to add a bit warmth to a new down bag, plus wanted to keep the bag clean. It's been a great addition to our Summer and Fall backcountry trips above 8,000' where it the temp drops off quite a bit at night. Thus far it has been versitile enough to add the extra warmth, but the stated amount of 15deg is a bit optimistic, but on warmer evenings (40-50deg) I found myself using just this liner and being very comfortable. The greatest bonus of this liner is that it is soft and very light for the amount of heat retention it has. It cleans up easy and doesn't retain much if any moisture. I've been impressed with this liner and just picked one up for my wife at the . We also fly a lot and I see us taking this with us on the plane too.
Great Liner, OK on its own
This liner is very good. I have used it a few times in conjunction with a zero degree no-name bag that was stuffed for many months... Lets call it a 10-15 degree. Anyway, it helped it out wonderfully, keeping me very warm, and it fit well in the bag, too.
This thing is freakin' tiny when packed, which is very convenient. I fit in it pretty well, which is saying something as I am 6'5".
Additionally, I have used it multiple times by itself as an uber-light bag, and while it keeps me warm, the thin material is not wind-resistant at all, so the slight draft in my tent removes most of the warmth it collects. I am working on making a windproof shell for it, we'll see how that turns out. If so, it could be a summer bag that fits in a Nalgene!
Warm and Lightweight.
i have used this liner 5 nights now, in preparation for a longer trip coming up...
first impression is it FEELS wonderful ! (my North Face Cats Meow feels plasticy to me) it is so thin it's nearly sea-thru and i was disconcerted seeing that, but i took a snooze in my tent mid afternoon on top of my sleeping bag and i was extremely warm (my feet began to sweat). it was in the 60's... it's not yet been cold enough to use it inside my sleeping bag for any length of time.
it really is extremely warm and lightweight, just what i was looking for.
i only hope it is durable, it is so thin it's hard to imagine a sharp toenail won't go right through it, no problems yet though (and i have toe-swords)