Sea to Summit Thermalite Bag Liner?

[crmiller84]

Worth it or not? I was looking at them to boost the rating on my 30* bag but wanted to ask around before pulling the trigger. The one I was looking at was the +25* model. No clue if their numbers are accurate, but if so that would make total weight for that setup around 3lbs 6oz for a 5* bag. I know I can do that somewhat lighter with down, but for the cost this seems pretty versatile.

 

[land cruiser]

I use it and move mine.

 

[Gumbo]

I have a 15* version that I only used once that I'd sell you for $25 shipped. It is in great shape, like new except for about 3/4 inches of stitching that is fraying on the stuff sack. PM me if interested.

 

[camping1601]

My wife has one and says it helps. She likes it and we didn't have to buy a new bag to keep her warm.

 

[LBFowler]

I think bag liners are almost always a bad idea. I found them a fussy, tangled mess that makes it that much harder to enter and exit the bag (I'm really groggy when I first wake up, especially in the middle of the night). Yes they add warmth but the weight/warmth ratio is pretty bad, as an REI employee told me when I was quite young, a good set of base layers does the same thing (add warmth, keep the bag clean) but they follow you outside the bag when you have to take a leak.
A breathable bivvy will also add warmth, but also protect the bag.
I would honestly rather use a cheapo fleece blanket inside a sleeping bag then a bag liner. More uses, less fussy and probably warmer, cut down to top-quit size not a huge weight penalty but still bulky.

 

[crmiller84]

The more I look into them the more I am thinking they are a less-than-ideal solution. I was trying not to spend the money on a new bag, but it looks like it is going to be the best option. I noticed Wiggy's has a sale going right now, so I may just try out one of their Super-Light bags. 4-4.5# for a 0* bag doesn't seem all that bad. I understand they're bulky, but I may just have to deal with it. $300-$500 bags just aren't in my budget right now, and I'm not a huge fan of the risks associated with down.

 

[teamvit]

I have one and I think I have used it more just as a stand alone during the summers months