>>195216>take note that bags have two ratings, comfort and extreme (or "survival")Well if you're talking about the EN 13537 European standard, which is the only one worth checking, it's a bit more complex than that, and worth learning exactly what it says. It's good for general information about a sleeping bag, but if you need more precision, you need to know all of the following:
It gives you three temperatures, determined by using dummies of a man and a woman. The man is 25, 1m73, 70kg, and in underwear: tshirt, briefs, knee high socks, and a thin beanie to simulate hair. The woman is 25, 1m60, 60kg, and in same underwear. They sleep in the sleeping bag, completely closed, on a 14mm thick foam mat.
These are the three temperatures given:
- Tcomfort: temperature at which a woman in a relaxed position feels just good: neither warm nor cold. It's the temperature at which anyone would feel warm.
- Tlimit: temperature at which a man, in foetus position, feels just good for a duration of 8 hours minimum, and thus can sleep. Basically, temperature at which you may get cold.
- Textreme: temperature at which a woman, in foetus position, is on the verge of hypothermia, and is only guaranteed to survive in this situation for a duration of 6 hours. Avoid this situation.
A fourth temperature exists: Tmax: temperature at which a man, in a relaxed position with his arms outside of the sleeping bag, is on the verge of sweating. We usually don't give a fuck about this one, for obvious reasons.
Should you take those temperatures for granted? Not really, it varies for each person, though they're overall good. Can they help you compare different sleeping bags? Definitely. They are all rigourously tested by the same European institute, which guarantees homegeneity between those results.
