The text is for one FB group and saved here so as not to lose it. The opinion of the author may not coincide with the editorial opinion. Having slept in a sleeping bag several times, even at plus temperatures, I can express my personal opinion, which may not coincide with the editorial opinion.
1. Serious manufacturers write 3-4 temperature values. Sometimes at each meaning, to the horror of all feminists, differentiating the temperature between men and women. No matter how much I blow their brains, but physiologically women need about 2 degrees higher temperature.
2. There are sleeping bags that have the ability to be fastened together and that way you will sleep warmer. Maybe it’s not so nice if the bedfellow is not a person you like, but a smelly colleague, but the choice is yours, you can freeze if you want.
3. The COMFORT temperature value (t) indicates the temperature at which you can sleep for up to 8 hours of uninterrupted sleep. LIMIT, LOW COMFORT or LOW LIMIT indicates to what volume. you can get up to 4 hours of uninterrupted sleep. The EXTREME value indicates to which t. you shouldn’t get hypothermia, but there’s no question of sleep here.
4. An old Ukrainian proverb says that Ch*i is written on the vegetable garden, and firewood is lying there. If you buy a sleeping bag with -40 for 10 euros in “Senukauis”, it can only mean one thing, that after consuming 40-degree noble drinks, you shouldn’t get cold at +14.
5. “Heats” not the cloth, but the air gaps in the filler. Remember the double-glazed windows. Glass is a very good conductor, but thanks to the air gaps between the glasses, the resistance increases. The filler can be synthetic or natural. As a natural filler, pucks are usually used, which are now sufficiently well impregnated and resistant to moisture. Synthetic filling, translated into human language, is threads, sometimes hollow, sometimes even multi-chambered. The warmth, weight, volume and … price of the sleeping bag depend on it.
6. In the place where you press the sleeping bag to the ground, the air gaps are reduced and that place will be cold. A little warmer with a good filling, but still cold. To solve this problem, people invented sleeping mats. Serious manufacturers write the thermal resistance (R) of the mats. “Old” thick blue ones are suitable after using 40 degrees noble ones, with the above-mentioned sleeping bag, so that the cones don’t slide into your ass, not to keep you from getting cold. Personally, I use the Thermarest NeoAir XLite NXT inflatable. Angry tongues say that it inflates badly, because if you puncture you will not have it at all, but in ten years of use this has not happened yet. And the R4.5 weight of 370 grams allows you to ignore the words of the envious. I recommend choosing at least R3.5 if there is a possibility that you will sleep on snow.
Good, warm and peaceful sleep to you and your loved ones.