The ability of insulation and comfort in a sleeping bag temperature depend on three fundamental characteristics:
1. Quality of the raw materials used in their manufacture.
2. Structure or design of the SAC.
3. Size and metabolism of the person using it.
1. Quality of the raw materials
• Of all the raw materials, the most important is filling, better to be one who is able to retain more heat.
• There are stuffed with down and polyester fibre. The first, if it is high percentage of down (90% down, 10% Feather) and high weight, has a higher calorific yield but low life expectancy; While polyester fiber has a low maintenance and long life.