Sleeping bags without bottom insulation

I have a synthetic Big Agnes bag that I use sometimes in colder weather (it is a 15 degree bag, I think). I have a full length InsulMat pad. This combo works Ok for me; I don’t recall any issues with respect to side-sleeping.

The really nice thing I found was the fact that the bag and the pad don’t get separated. In fact, I appreciated that so much that I considered trading in my WM Megalite for a Pod30.

My current strategy is to put the pad *inside* my bag. I did that in my hammock over a trip July 4th. Seemed to work and I think I’ll stick with that technique rather than get a new bag.

If you have the pad already, you might try that trick to simulate the effect of the other style sleeping bags. It has the same effect of preventing you from folding the bag into a shape that doesn’t conform to the pad.

Does anybody else do that? My only concern would maybe be increased wear on the bag when sleeping on the ground.

Bill Law

My Big Agnes has a slit that accommodates the Big Agnes pad. I roll all over when I sleep and have had no problems. Camped near a lake at 9500 feet last week and was perfectly comfortable. In the morning, I noticed new ice on the lake.

One problem: if you are not camping on a reasonably flat place, the whole contraption slips to the low spot.

I’m hanging onto my Horsethief, a first year model, maybe changes since. Mine is very warm, well made, roomier than most and very affordable since imported. The pad sleeve works very well, no insulation at all on the bottom.

I cut a now extinct Mt. Washington foam pad for exact, tight fit, omitting the head and upper neck. I use a foam or bubble wrap pillow sewed into the upper end of the pad sleeve, nothing loose inside the bag that way. Makes the pad just that much smaller when rolled.

Mt. Wash equivalent is available from gossamergear.com. Careful when cutting, pad gets too small all of a sudden. I wrecked one. Bit by bit, no more than 1/4″ trims when getting close to a fit.

I think this is a winning idea, but it doesn’t seem to have caught on much, don’t know why. Horsethief has no hood, strange since you will need head insulation below 40-45 F for sure. I could go to freezing with this bag, wear down liners to go lower if need be. Just carry insulated headwear, which is therefore dual use, not a bad thing.

Certainly not a winter bag, but warm enough for those Sierra (And San Jacinto, San Gorgonio) nights near freezing, or for freak cold storm protection, IMO. For the 3 seasons.

Best, Todd in CC.

I just finished a four night trip in the Eagle Cap Wilderness of northeastern Oregon. The nighttime temperatures were down to 32 degrees twice, judging by new ice on a lake one night and frost on the ground another. I use a full length rectangular thermorest mattress with the Big Agnes Horsetheif. I had the bag modified at a local sewing shop in order for the rectangular mattress to fit inside the sleeve. I was very comfortable and got by with wearing underwear breifs and a long sleeve light top. I changed sleeping positions frequently, as usual, and it felt like I was sleeping in a twin bed.

David, I have a BA Mica bag, ’03 model, 20 degree rating.. When I first got it I cut reflectix to fit the mummy shape. This was warm, but not as comfortable as I would like. I decided to add the weight of the BA aircore insulated pad. Much better, but I sleep cold, so if the temp drops I take the foam pad from my Gossamer Gear Mariposa and slip that under my torso. Haven’t been cold since. On warm nights in my back yard here in NH, I sleep on top of the bag after inflating tha mattress. I have not had any trouble falling off and I do toss and turn. It is true, as stated in a previous response, that you will slide a bit to a low spot, but that is probably true with any sleep system. I agree that the concept has not been received as well as it should, but I recommend the BA product to anyone.
Hope this helps.
Jim Ells

Some comments, I have been using a Macpac neve for about 10 years now, which is a top bag with 450g (15oz) down cut to fit a rectangular thermorest. Usually fine just below freezing with baselayer, not much more. Am not convinced I would buy a similar bag again. In order to be able to roll over etc, needs to be quite roomy which significantly detracts from warmth, also the neck is difficult to seal well due to stiff mat. I think bags cut to fit a mummy mat would be better here, but then if you move around much they will be too tight. I certainly dont think they are twice as warm as as a normal well made trim bag with the same amount of down.

Thanks for everyone’s input. Much appreciated. I will post what I purchase shortly. This may have been said before, but I wanted to express my gratitude to those who post on this site: great honest, and usable, information.

I am a side sleeper and find that the BA mummy bags/pads do not allow me to flex my knees as much as I like. The regular bag/pad is great.

YMMV