Moisture accumulation in sleeping bags at subzero temperatures - effect of semipermeable and impermeable covers

Because subzero temperatures are expected to affect the vapor resistance of microporous membranes, the effect of using semipermeable and impermeable rain covers for sleeping bags on moisture accumulation in the bags during 6 days of use at -7degreesC is investigated. Moisture accumulation is related to the vapor resistance of the materials. The best semipermeable material gives the same moisture build-up as no cover. Semipermeable cover materials are effective at reducing moisture accumulation in sleeping bags at moderate subzero temperatures.