Some U.S. companies of backpacking sleeping bags have complied with the European Standard (EN 13537) technique of temperature level screening. Without entering into excessive deepness about exactly how they reach these numbers, generally they check the best sleeping bags under strict standards using a clothed dummy sporting long underwear and also a hat. Sensors on the mannequin document temperature readings.
One more item you could acquire is a sleeping bag liner. These offer extra heat on cold evenings, as well as can likewise be gotten rid of and washed, conserving your sleeping bag from the regular damage.
Remember that with time, from typical use, a treking sleeping bag will certainly lose its warming performance. This results from the fill obtaining a bit much more compressed. This will cause the "air pockets" to go away.