Qualities of a sleep layer

https://www.patagonia.com/product/mens-capilene-air-bottoms/36555.html?dwvar_36555_color=CNY&cgid=mens-baselayers#tile-3=&start=1&sz=24

But heavier than your desired weight

Thanks. I’m not necessarily after specific gear recommendations, more a broad conversation about how to maximise warmth in a static baselayer (specific recommendations around particular properties are welcome though).

Since I started backpacking seriously in 1980 I always had some kind of leggings and top baselayer for sleeping.  In the old days it was that stinky blue polypropylene which itched and melted in the dryer.

Now I use merino Icebreaker leggings—200 wt in the summer and 260 in the winter.  They become both pajamas and a hiking layer under shorts in the winter (the standard AT-Hippie Look).  Smartwool merino leggings are also good.

But the most comfy option I think is getting a pair of pure silk leggings and using these for sleeping, both tops and bottoms.  Sleeping bare skinned on nylon sleeping pads and under nylon sleeping bags or quilts often gets clammy, and so the need for a lightweight and ultra comfortable baselayer.

Thanks! I wonder how silk compares for warmth:weight?

I find all baselayers comfortable enough to sleep in (especially compared to nylon pads and quilt shells), so ultimately it kind of comes down what material has the best warmth:weight ratio I think.

anything like merino or fleece or fabric has poor warmth to weight ratio

2.5 oz Apex would be good.  A legging is about 1/2 square yard?  One square yard for two.  Use 0.7 ounce/yd2 fabric on inside and outside so that would be about 4 ounces total.  But the Apex would give some real warmth.  merino/fleece/fabric wouldn’t give much warmth.

You’re right. It’s as much about comfort (skin feel) and keeping sleeping quilt and pad clean. If the pants are just for sleeping, it’s more efficient to have a warmer sleeping bag than to have apex pants (unless those apex pants are already being used through the day).

FYI englightened equipments 2.0oz apex pants are 5.5ish oz for about an average size.

The reason I’m trying to understand the warmth of the different fabrics (even if poor) is there are generally options in each fabric around 3.5-4oz, I find all comfortable, so I may as well maximise any potential warmth advantage one material might offer

EE Torrid pants (2.0 oz Apex) are just over 5 ounces if you get the lighter fabric (7D/10D inner/outer would be good).  You wouldn’t need wind pants over them unless it’s very windy out.

If you don’t need that much warmth I would find some light leggings but getting a pair under 5 ounces that aren’t thin/wicking material will be tough.  I find my Capilene Thermals to be very comfortable and warm, 5.6 ounces for Large.

YEah, too warm and I will have wind pants anyway for ridge walking and breaks.

You might be right. I have a 7-8oz pair of leggings which do well, but perhaps getting too light would lose any quantifiable warmth. I’m hoping to replace the heavier leggings with windpants and light leggings that are the same weight or lighter in combination. Theoretically a more versatile combo

I think your best bet then is grid fleece leggings.  The gaps allow you to have a lighter and more packable layer and still just as warm when you put on your wind pants.  As long as they don’t fit too tight then you will be fine to sleep in them.

I sleep in silk base layer top & bottom in spring and fall. They feel great next to my skin, are very light and pack up small. They’re too warm for summer use. For summer it’s a short sleeve syn shirt and syn shorts.

I tend to hike in mount mountains so even in summer I’m rarely overheating;)

I initially discounted grid or fishnet patterns. They’re quite efficient when “capped” by a vapour barrier (eg wind pants), and the grid pattern helps wick sweat (I believe). But this makes them less optimal in a quilt, as the quilt will rarely be an “ideal” distance” to create pockets of warm air in the grid. But it will be good around camp. Maybe the latter is more important to focus on since adding more quilt weight is always going to be the most efficient way to add more warmth to a sleep system – so then the primary purpose of the sleep layer is comfort. Hmm. Thinking “aloud” here.

I like the smartwool light weight (“150”) long underwear bottoms and shirt for sleeping, The wool feels way less clammy than the capilene (or polypropylene LIFA)  I used for many years. Wool just feels better against my skin. If I am sleeping on my side with my knees together, the wool feels comfy and dry. Synthetics, on the other hand, in that situation, feel clammy and sticky.

Hi Johanthon

I posted more because that underwear has a very open weave with minimum fibre and big voids and is as light as I have ever seen.

Polartec Alpha with an UL shell perhaps if after synthetic, down rules in the UL insulation race but the law of diminishing returns does kick in somewhere