Bivy in winter vs switching to sleeping bag

If you are already inside a shelter, a bivy is not a weight efficient way to add warmth, although if you have draft issues using a quilt in cold weather, a bivy can help with that to some extent. A warmer quilt/bag , something with maybe 3 oz more down, will add more warmth than a bivy for less weight.

Another thing you might try, is a warmer hooded jacket, or even just adding a separate down hood in addition to the EOS jacket – but the added hood will only be efficient if sized to go over the jacket hood.

Insulated pants? A thicker pad? The RidgeRest Solar is warmer than the Z-Lite

I found I was much warmer when I swapped to a long wide pad system but I couldn’t get used to a quilt in winter and changed back to my sleeping bag

@ Nathan

I  used an old BPL branded bivy manufactured by Oware Gear with a water resistant top when snow camping under my MLD Duomid. I agree with Paul’s comments about about the bivy not adding much insulative warmth.

But the bivy does cut down on drafts, enables me more easily to mitigate snow and frost from getting on my sleeping bag, and provides a place for me to store extra clothing and other items at night.

If you were using a more open tarp or if you are an exceptionally restless sleeper, a bivy would be a big help at preventing drafts, but if you are pitching the Khufu to the ground and sleep calmly, a bivy won’t be a big warmth boast.

My first question would be is your pad warm enough?  After you settle in for the night do you feel cold creeping in from the bottom?  If so, swap the Nemo for a warmer pad.

If you aren’t feeling a chill from below, then you need something warmer on top. You could add / change… warmer jacket, an insulated vest, a thick down baklava (love mine), a second quilt, etc, but I would suggest that if you regularly do winter trips, go for winter oriented bag or quilt.  Choice something that by itself is comfortable for your “normal” winter conditions, and uncomfortable (but “safe”) in the worse case, and comfortable in worse case when used with your clothing.

I suggest this for two reasons.  (1) It’s simpler and less fiddly… less decision fatigue when planning a trip.  (2) For cold trips it will be lighter than multiple items brought specifically for sleep.  Adding down to a bag / quilt is at least 2x more warmth / weight than adding an additional layer which has  insulation + shell,

The last thing to consider is how quickly you go from active to in your sleeping system.  According to some old charts , at 0F you need to be surrounded by a loft of  2.5″ to sleep,  1.3″ doing light work, and  0.35″ when active. If you don’t lounge around outside your bag, then it’s unlikely your clothing is going to be a significant enough boast.

Finally, remember that people’s metabolism varies widely… go with what works for you.  When I purchased a WM Versalite in 2003? it was “rated” for 20F.  I leave it unzipped until it’s below 0F or I roast.  My wife thought it was perfect at 40F.

Random thoughts about sleep systems https://verber.com/sleeping-bag/

PS: while a quilt is warmer / weight than a bag… I found that when it’s below around 20F, there is something psychologically comforting burrowing into a puffy bag… it “seems” warmer than a equiv quilt.

PPS: if you were looking a colder conditions I would think about a vapor barrier.

My experience with all bivy sacks I’ve tried, including ones from WPB fabric, is that all your condensation issues will just be moved to INSIDE the bivy sack – exactly where you don’t want it to be. I’ve never used one that did not soak my sleeping bag. I’ve never tried one with just a mesh top layer, but that wouldn’t add much warmth.

Winter sleeping hints:

1. place outer clothes like pants under your mattress(es) for more warmth
2. zip up your parka or GTX shell, cinch the hood and put fully over your the foot of your sleeping bag (makes the bag foot warmer and keeps tent frost from melting into your bag.
3. wear a light fleece balaclava
4. wear light knit glove liners (I know, sounds stupid – until you try it.)
5. ** put boot liners into the foot of your sleeping bag for warm feet in the morning & telescope outer boot tops together to keep out spindrift snow. You only have to have painfully cold toes once to take this advice seriously. Don’t ask..

If you do buy down pants be sure the down is DWR treated and it helps if they have at least half length leg zips.

@n8fyn – my Decision Matrix.

The question: “What’s the best way to spend weight to minimize condensation buildup in your sleeping bag?”

Possible answers:

1. more clothing insulation
2. more sleeping bag insulation
3. an outer quilt
4. a water-resistant breathable bivy sack
5. a waterproof-breathable bivy sack
6. an inner tent

1, 2 – more insulation inside the bag draws the condensation point further inward and will make it harder to dry the bag out; but is better for in-camp comfort and versatility;

3 – places the dew point in the outer quilt, which can be thin and light and easier to dry out; or synthetic and less sensitive to loft loss due to moisture buildup;

4 – increases the chance of condensation buildup on surface of bag which can wick into insulation; less airflow at surface of bag results in lower heat loss gradient and more condensation inside bag; good system when it’s windy and temperate;

5 – similar to 4 but even worse in cold temps, but better when you need to keep precip off the surface of your bag ie, heavy rain under a tarp or sprindrift in the winter; ok if you expect high winds and/or precip and/or extreme frost inside tent in very very cold temps;

6 – helps keep inside walls of tent drier where bag can contact them, minimizes accumulation of condensation on surface of bag; adds some warmth and draft protection to inside of tent.

I generally recommend #3 for extended trips in subfreezing conditions where accumulation of condensation can reduce loft of a down bag over time.

In very cold winter conditions I like a combo of #3 and #6.

Under a tarp in the winter I prefer #3 and #4 or #3 and #5.

I never combine #4/#5 with #6.

I’m always a big fan of #1 because it adds versatility, comfort, and safety in camp.

I wouldn’t spend money on the masterclass to answer this question alone – this one is really meant to provide a more holistic view of lightweight backpacking in inclement conditions.

The next class I’m teaching is specifically about winter conditions and I’ll address this topic in a lot more detail, including how and when VB fits into all of this.

I agree about a synthetic “topper” quilt for your sleeping bag. It adds warmth and, importantly, holds most of the condensed moisture from your body.

I happen to have a Thermarest synthetic quilt that attaches to a sheet which covers a Thermarest Trail Pro mattress but I’ve added 3 one inch wide elastic strips to go under my winter mattress and hold it on my down bag. I estimate it adds about another 10 F. to the bag. Along with a heavy base layer and puffy pants and jacket it can take my 20 F. down bag to around 5 F. The topper does dry fairly fast in the morning and is ready to pack after breakfast and breaking camp.

If you want to really sleep warm inside a down bag—get an Exped Downmat of whatever configuration.  It comes in at 8R and you’ll feel a tremendous amount of heat radiating back up to you from below.  Have to try it to believe it.

BUT it’s not the perfect sleeping pad—inflation is cumbersome (in my opinion) and there’s always a tendency one of the baffle seam-welds can blow apart.