gauvins

We have 40F rated down bags and are planning a trip where the average expected minimum temperature is 37F. So we are planning on a freezing night or 2. We may be able to find some kind of accommodation if the temperature were to drop way below normal, but would rather be safe (read -- "warm") than sorry.

We sleep in a single walled tent.

We have silk liners. We have head gear, thermal undies and metal bottles that could be filled with warm water. We also have emergency blankets that can be used next-to-the-skin or as a sheet, over the bag.

(1) We have to purchase new sleeping pads, which brings this specific question: One is rated R 3.2, the other R 5.7. The penalty for more insulation is something like 150 grams (5 ounces) and $50. does it make a meaningful difference? (therm-a-rest claims that it does...)

(2) What about sleeping bags covers or bivies. Said to extend the range by an additional 5-10 degrees F. Hype or not?

Other tips appreciated. Really don't feel like spending a small fortune on warmer bags.

fietsbob

wear more clothes to bed.. I loved my down filled airmattress.









Reflective mylar foil as the inside liner-vapor barrier trying to stop evaporating sweat is the goal.. it will feel clammy because the sweat is not evaporating..



....

tspoon

I've got the Sea to Summit brand thermal liner, which uses a hollow fibre called thermolite. I got the 'extreme' version which claims to extend the temperature rating by 14C, although I think the actual extension was somewhat more modest than claimed, and the liner weighs 400g which is a substantial fraction of the weight of a sleeping bag itself. But it may suit your needs.

Another method may be just to take thermal underwear or your winter riding cycling gear (assuming it's not too bulky) and use that if you find you're getting too cold. You can also use the gear if it's cold in the morning when you start out. Cheaper than buying anything too.

Leebo

Rent something warmer? Got some vapor barrier( see tyvek) for the bottom layer. I've been cold, not good. Got some of those chem heat packs? Packing a lightweight down puffy? I like to carry a full set of warm layer off bike clothes. Warm hat and socks plus layers work for me.

alan s 

You always have extra clothing you can wear and towels, etc. you can add over the sleeping bag. Should be fine, unless you are a minimalist. If so, then prepare to suffer.

LeeG

If you don't want to spend money on a new bag pick clothes with multiple uses in bag and on the road. Liners are nice for keeping inside of bag clean and thicker ones extend temp range of the bag but a nice Merino wool sweater or tights will do more to keep the heat in your body and have utility out of the bag.

gauvins

msquared22

Yes, an R value of 5.7 will be much warmer than 3.2. (I assume you're looking at an XTherm vs the XLite?) I sleep a lot warmer on my XTherm.

How long is your trip? What's the coldest you've slept in these 40 degree bags? Are they honestly good down to 40 degrees? I get cold in my "20 degree" bag well before it gets down to 20 degrees. I wouldn't want to be worried about freezing at night. I've had some long, cold nights before and they're not fun.

mstateglfr 

yeah...ive never found a bag that i am comfortable at the listed rated temp. that rating is for something like what its able to keep you from getting hypothermia at, or something like that.
a 40degree bag being used for anything below 60degrees will mean I am cold.

...and i have some built in insulation.

Erick L

I use a Xtherm and had a few nights at much lower temp than my sleeping bag's rating (like -10°C in a -3°C bag). I woke up a few times when my down jacket slipped off my bag but it was surprisingly comfortable. I didn't even close the bag and used it as a blanket, like I always do.

Tourist in MSN

I have used a 40 degree bag when there was frost on the ground, but it was above freezing in my tent. Your tent will add several degrees, so I think you do not need to worry about 37 degrees.

I assume you have slept outside when it drops below freezing before. But if not, think about anything you have that contains water in it. Water bottles that you can't get the lids off later because they are full of ice, cans or bottles of wet food (soup, soda pop, etc.) can be damaged. A water filter that has some water in it can crack, I always bring my filter into the tent if it is going to be cold outside at night, a friend of mine had his filter crack in sub freezing weather. Cooking pots that have ice in them that has to be removed before you can make food or pack up. Etc. Even if the forecast is for above freezing, in localized low spots it can get quite chilly and below freezing.

Yean bring your liners. I have not found liners to be effective at adding warmth, but others disagree with me so maybe they work and I just have not noticed it. I use a liner more to keep my sleeping bag clean than for warmth.

Head gear, I assume you mean something like a stocking cap. Absolutely. I usually sleep with a stocking cap when camping in cool or cold weather. One that does not have a tassel on top since the tassel gets in the way. A skull cap shape made from polartec or something warmer like wool would be great. An acrylic stocking cap that is more for looks is not very effective, if you have one leave it at home and get a better one.

Thermal undies, yeah wear them.

Metal bottles with warm water, skip it. They won't add much warmth for 7 or 8 or 9 hours. You do not need that much warmth for the first hour or two, you need warmth at 4 or 5 am and by then the water will have reached an equilibrium with the temp inside the bag.

Emergency blankets, I think you are best off to not put over the top, maybe put them under the sleeping pads on top of tent floor if you think that they can add some insulation value. (Years ago a friend of mine used to use a space blanket on top of his tent floor for winter camping for the insulation value.) I say do not put on top because you want moisture that gets into your bag to be able to escape through the shell of the bag. But, if you are really freezing and will have an opportunity to air out your bags later, then maybe the short term gain of warmth might help a bit?

Sometimes in cold weather I have draped a down jacket or down vest on top of my sleeping bag in the torso area. But never anything else because a down bag will easily compress so you do not want to put anything that is denser than down on top as that could compress your insulation.

No opinion, I have no clue what any of my pad R ratings are. I have only worried about the insulation value of my pads when sleeping on top of packed snow.

I would not bother with additional covers. Recall my comment on compressing your down insulation. You are already in a tent that will trap some heat in it.

I have a regular length winter bag but I should take a long one. My feet can compress the bottom of the bag because of the shorter length. I have found that down booties or down socks really help in that bag. If you occasionally get cold feet at night (some people do), consider warm socks at night. But if your feet start to sweat, then maybe the socks are not a great idea.

M69thunder

I've been looking for something that will wick away the moisture and drys fast... everything I've tried so far becomes damp, then 4:00am, I wake up chilled to the bone. I actually seem to do better not wearing anything. Just got a new down quilt, they recommend wearing something, mostly to protect and extend the life of the quilt. I've reviewed some silk long underwear, the reviews make me a little nervous about spending that much money on something that may not holdup. Anyone here have any experience with silk? Good or bad.

52telecaster

this thread is making my feet hurt in anticipation of winter. i would just reiterate what others have said. i used a 20 degree bag in 37 degree weather and it was ok but i would have been miserable in a 40 degree bag.

Shadowx

in my experience the mat is paramount. if its cold and the ground is cold the ground has a much larger thermal mass and will suck the heat right out of you. In my opinion a mat is 99% for insulation and a 1% of comfort.

Don't forget the sleeping bag and tent rule. Add 10F to the bag temp, the rated temp is the one that will keep you from freezing to death, not comfortable. And however many the tent says take 1 off of you plan to me comfortable and not spooning. With the gear you have i would think you would be in decent shape.

CliffordK

Camping together? What relationship? You can get zip-together sleeping bags Can one get a hot and cool bag to zip together? Look for bags that have a square foot area and zipper that goes all the way around so the bag opens up flat.

One important thing is insulation from the ground, so a good ground pad may well be worth more than a thicker sleeping bag.

As mentioned above, wear clothes in the sleeping bag. Something like a fleece sweater might serve multi-purposes including an evening & morning camp shirt, as well as for riding on those cool or wet days (with a slicker as needed).

BigAura

Layers = warmth

Clothes-layers are flexible because you can wear them in the daytime too.

-- OR --

A second sleeping bag/quilt will keep you toasty.

I'd avoid anything that doesn't breathe. Those emergency blankets should be used for EMERGENCIES and not for daily use. If a 2-ounce blanket was truly comfortable for extended use, EVERYONE would be using them...all-the-time

ALSO: R factor on ground insulation is for-real. R-5.7 --> get it.

Stormsedge

When my son was scouting in Nebraska, we bought several yards of polar fleece at the fabric store and my wife sewed a liner for his 10 degree mummy bag...a good thing as it did go below zero and ice stormed. I think he was awarded a clear bead for that little adventure--LOL.

prathmann

I actually do use a layer that is totally non-breathable and waterproof whenever the temperature drops below freezing and have been comfortable that way in my nominally 30F bag down to 0F. The trick is to put this layer right against the skin so it holds in any moisture. As long as you're not overheated and your skin is moist, the pores shut down and you stop perspiring and therefore stop losing heat from evaporation. This 'vapor barrier' also prevents any moisture from getting into your bag so it maintains its full loft and insulating power. A secondary benefit is that I wake up less thirsty in the morning.

I actually came across this method by accident on a trip where the weather was much colder than predicted. Started shivering during the night and remembered that I had one of the 2oz mylar sheets along for emergencies. I wrapped myself in it and got back into my sleeping bag and was very comfortable for the rest of the night. Later read about vapor barriers and realized that that's what accounted for the added warmth. BTW, the mylar type is rather noisy and I now use a waterproof nylon liner instead.

But note that vapor barriers should only be used when it's really cold - below the normal comfort range of your bag/pad combination. If you start to overheat your body will start sweating like crazy trying unsuccessfully to cool you off.

gauvins

Thanks everyone for your input. Takeaways so far:

Very, very good point indeed. Thanks for bringing it to my attention.


That settles it. Read a bit more about R-Values. On the surface 5.7 looks to be close to 3.2. OTOH 5.7 is 78% more than 3.2

--

I'll get the pad and sleep in the backyard when the forecast will be for close to freezing at night. Unfortunately, it won't take long to get there... (neighbours will wonder if we had an argument! )

DeadGrandpa

One more thing you can do is get one of those windshield sun/heat reflectors, with shiny foil over bubble wrap. Put it on the tent floor under your head and torso, under whatever pad you have. Unless your pad already has a foil layer.

irwin7638

I use a vapor bag and also put toe warmers on clean socks before going to bed.

Marc

andrewclaus

My favorite pad in cold weather, and especially on snow, is to augment my regular closed-cell foam pad with a piece of Reflectix duct insulation. It's available in 24" wide rolls, and the extra can be used for a pot cozy or even its intended us as duct insulation in the home.

Nobody can predict how you'll feel in a 40F bag on a 35F night. Much will depend on your fitness, hydration, and food intake.

The hot water bottle trick in the sleeping bag is a real good one.

I've noticed there's a break-even point on wearing clothing to bed--too much will restrict your movement and actually make you colder.

Sorry for repeats, I haven't read every post.

alan s 

Wouldn't worry about compressing the bag with an extra layer on top. Jacket, towel, extra clothes, etc. Even if you lose a small amount of loft, overall you will be warmer. For me, it makes enough of a difference that I'm no longer cold, so all I can say is don't rule it out because someone says it won't help. Try it for yourself.

Doug64

+1
We often use our insulated jackets (Primaloft) on top of our sleeping bags for added warmth when snow camping, and climbing.

The jackets are filled with the same insulating as the sleeping bag; why would it compress the bag's insulation?

With the new synthetic insulating material, I retired my down bag.

bikenh

This is definitely not the answer you are looking for, at least if you are like most people on here...but it a rather interesting different way to think about the situation at hand and to have a whole new kind of experience on a bike trip.

Sleep during the day and ride during the night. Experience where you are going to ride under a totally different set of circumstances. Now you sleep when its warm and ride when its cold. Your body warmth, aka body pedaling the bike will keep you warm over night while the sleeping bag will keep you warm during the day while you sleep.

Could provide a nice chance, depending on where you are going, to see the northern lights while riding the bike...have you ever did that before?

On the normal side of the equation...the one thing I have learnt many times over is anything placed directly on top of the body, no separation to the outside air will provide insulation. Placing a rainfly directly on top me on a 60 degree night, no other protection, no tent, no sleeping bag, keeps me warm. I would be cold without the simple piece of nylon tossed on top of my body. You just need something to help trap the body heat in and it needs to be placed directly against the body/clothes you have on, no air gap between it and the body/clothing.