Sleeping bag with liner

[Mappage]

I currently use a 20* North Face bag that is great in functionality but not in size. I have been looking around for a new bag for a week or two and reading as many reviews as possible but i haven’t seen many discussions on liners.

My potential purchase:
I'm looking the Sea to Summit Spark 46* bag because it is super light and packs down to a very small size. I'm fully aware temperature changes can be drastic and drop to 20* without warning (like last weekend when I was on the AT in VA) so I was thinking i could pair the bag with a Sea to Summit bag liner. They advertise various liners that can add up to 25* of warmth to your bag.

My thought is i would only need to pack the liner when needed and then keep it out during the summer months.

Any advice is appreciated.

[HooKooDooKu]

I've never used a liner myself, but I have done a little research in the past. It seems like most of the reviews place the actual warmth gained by liners at much lower than the advertised value. So while I don't have any hard numbers, I've come to the conclusion that any sleeping bag + liner is going to be heavier than an equivalent warmer sleeping bag. In other words, I think you'll do better getting a 30º degree bag and a 15º degree bag rather than a 30º bag and a +25º liner.

For summer use, I experimented with a fleece sleeping bag. The bag was only good down to about 55º and weighted about 2#.
Once I found a 2# 32º bag, I purchased that to use when ever the weather called for temperatures down to about 40º. Then I change over to my 3# 15º bag for when temperatures are going down to about 25º. (Below 25º and I currently don't plan to hike).

[Chopsbenedict]

i have thought about the sea to summit liners as well (REI), and was wondering if anyone had compiled any data comparative to bags, i.e. not an added warmth but a temperature rating. most of what ive read here says to count on less than the selling point in terms of warmth out of the liners commercially available. so if i have an advertised +25 deg liner (call it a real-world +15) and sleep comfortably at X temperature, could i consider it an X-15 bag?

[OwenM]

I have a S2S Reactor that supposedly adds "up to 15F of warmth". It is comfortable alone at room temperature indoors, and in my tent during the warmest summer nights(in AL). About like having a sheet over you, and I'm an exceptionally warm sleeper. Looking at the required increases in down fill and loft to lower a sleeping bag's rating 15-25F, the manufacturer's claims for these liners must have involved some very vivid imaginations. For perspective, Western Mountaineering used to have a 14oz liner bag called the Linelite with 1" of loft per layer, 2" total. Their claim was that it added 15F when used in conjunction with sleeping bag. If you look at their current specifications chart, their 15F bags have 6-7" of loft while their 35F bags have 3.5".

[mattjv89]

I have a sea to summit liner like OP is looking at, the reactor extreme 25 and have found nothing extreme about its performance. I wouldn't give it more than 10* of added warmth, I mean if you stretch the fabric out you can see right through it. It has been nice a few times to prevent icicle toes when using a bag close to or at its rating, but would never count on it for conditions below the bags rating

[slbirdnerd]

I've heard and mostly believe all the same things about liners, however, I did pick up a S2S Reactor Extreme to add to my 23 down bag, just to try it. I'm still curious to see what it will do, but right after that I stumbled upon a Western Mountaineering bag for sale used which I'm sure will fill the bill. Meanwhile, for summer-ish conditions, I plan to use the S2S liner with my 35 degree Thermarest down blanket. I'm eager to see how that works this weekend.

[Venchka]

I currently use a 20* North Face bag that is great in functionality but not in size. I have been looking around for a new bag for a week or two and reading as many reviews as possible but i haven’t seen many discussions on liners.

My potential purchase:
I'm looking the Sea to Summit Spark 46* bag because it is super light and packs down to a very small size. I'm fully aware temperature changes can be drastic and drop to 20* without warning (like last weekend when I was on the AT in VA) so I was thinking i could pair the bag with a Sea to Summit bag liner. They advertise various liners that can add up to 25* of warmth to your bag.

My thought is i would only need to pack the liner when needed and then keep it out during the summer months.

Any advice is appreciated.

More date required. Filling in the blanks:
"but not in size": Packed size? My guess: Either an Aleutian or a Blue Kazoo or a Cat's Meow. Which? All of these are 2 pounds + up to 3 pounds +.

The only things that you can place inside a sleeping bag that will add heat to the inside of the sleeping bag are YOU and bottles of hot water.
Sleeping bags prevent the loss of heat (see above sources of heat) with the use of dry insulation.
The thickness of dry insulation and the still air contained in the insulation layer determines the efficiency of the insulating layer.
The down from waterfowl raised in cold climates has proven to be the most efficient insulating material for sleeping bags that are carried long distances by the user.
Western Mountaineering specifications indicate that a doubling of loft (insulation thickness) with a 60% increase in down filling is required to lower the temperature rating by 25 degrees. Mitylite & Apache MF used in this case.
There is no free lunch. :cool:
Personally, I think that Sea to Summit should be cited for criminal false claims.
Buy a good 20 degree down bag. There is a good one (WM Ultralite) for sale right now here at WhiteBlaze.

Wayne

[he.who.forgets]

I little off topic here but didn't want to start a new thread. For those that DO use liners, when you pack up in the morning, do you leave the liner in the sleeping bag and stuff it all in the same stuff sack or do you pack the bag and liner separately?

[Venchka]

ps: Once upon a time I tried to cheat Mother Nature on a bike trip through Utah, Wyoming, Montana & Idaho (counterclockwise circle from Salt Lake City to West Yellowstone and back) in mid-July. In an effort to cut weight, I left my 32 degree down bag at home. I carried a fancy 3 layer sleeping bag liner. The middle layer is a reflective material like a space blanket or the inside of an Xtherm air mattress. I also had wool long underwear, down vest, hat, gloves, etc. All of which probably weighed more than my down bag. I was ok at low elevations in Utah & Idaho. Up in the Wyoming high country, Grand Teton & Yellowstone N.P., I froze my behind off. It wasn't even that cold, not even close to freezing.
This was before the internet educated all of us on such matters. I learned the hard way.

Wayne

[Venchka]

I little off topic here but didn't want to start a new thread. For those that DO use liners, when you pack up in the morning, do you leave the liner in the sleeping bag and stuff it all in the same stuff sack or do you pack the bag and liner separately?

I would let both air out and dry as best I could in the morning and pack separately. If I felt that the liner was really damp, I would strap it outside my pack to dry and air out.

Wayne

[squeezebox]

I was unimpressed with the liner. Difficult to keep in place when turning over. not much warmth, certainly not + 25*, and 10 oz. wt.
add 10 oz to the sleeping bag will probably give you more warmth.
my guess is a good pair of longies are lighter and warmer than the liner. and can be used during the day if needed.
MHO