I am a fan of synthetic gear, as it is cheap and the material science is going to catch up with mother nature rather sooner than later. I have two sleeping bags, Marmot Trestles Elite 20, and Marmot Trestles Elite 0. I like both but find the latter very bulky. I am contemplating getting a beefy liner (like, S2S Thermolite Reactor Extreme) for the lighter bag instead of carrying the warmer one.
Does anybody have experience with the combination of a liner + bag vs. warmer bag? How well do these options pack compared to one another.
I have a BD Cirque 45 for winter ski trips (it looks like it the largest ski backpack on the market), but it lacks straps for the external attachment of the gear, so every cubic inch inside counts. I am worried more about volume than the weight.
@Dmitry Thanks for reaching out and starting this really good discussion!
While I haven't used the Thermolite Reactor Extreme, I am a proponent of layering your sleeping bag system for extra warmth. Much like laying your clothing with a base layer, mid layer, and outer layer, using that technique with your sleeping bag system can hep you warm when the temperatures drop. In winter in the lower 48, I've used a really light +45° F synthetic sleeping bag inside a Big Agnes +25° sleeping bag that had no insulation on the bottom (essentially an overbag) with great success in temps down to zero, along with a +15°F sleeping bag with a 0° bag draped over it like a backpacking quilt while winter camping in temps well below zero in Alaska.
The trick is to really be thoughtful about taking steps to start warm when you get in the sleeping bag: doing jumping jacks or sit ups to get the blood flowing, making sure you have gone to the bathroom prior to sleeping, or eating a snack with fat in it to give you a slow burning fuel over night can all help you start (and stay) warm. You can also add a Nalgene bottle with hot (but not too hot!) water into your sleeping bag with you, placing it between your legs or near you armpits to help warm the blood flowing through your major arteries to help keep your toes and fingers warm.
You can also add layers to your body, wearing a light down jacket or insulated pants (likely items you're already carrying) to sleep. Combining these techniques with a packable sleeping bag liner should have you sleeping nice a toasty on your winter ski trips.
Hopefully this helps, I'm interested to see what other ideas the community has as well!
It should add around 15 degrees but I hate the feeling of being wrapped up to the point where I can't move at night. You may want to stop by the store and try it if your like me...
@REI-JohnJ has some great suggestions. I prefer to put my Nalgene with hot water in the foot of my bag. Layering gives more opportunity for adjustment. I have found that socks on my feet help me sleep warmer, followed by dry and clean long underwear tops and bottoms. I would rather sleep with a lightweight toboggan on my head than clinch the hood of my bag around my face.
@Dmitry I take an empty bottle to bed and fill it with warm liquid during the night -very efficient, just screw the lid on tight.