Sleeping Bags for Every Season A study of sleeping bag thermal resistance John Myers & Devin Anderson

Problem and Objective: Sleeping bags are rated only by lowest temperature they are usable in How can you combine sleeping bags and make sure you're warm enough for the climate? Determine and plot relationship between temperature rating and thermal resistance Use plot to determine effective temperature rating of combinations of sleeping bags

Method: Place a heating pad with a 180 Watt power output in sleeping bags with various temperature ratings Wait a sufficient time to reach steady-state conditions Use thermometers inside and outside bag to determine temperature drop Use relationship Q=( T inside – T outside )/R total to find thermal resistance of each bag

Results:

Conclusions: Data points are based on available bags and would be more accurate with a larger sample size of temperature ratings, and multiple bags for each rating There may be variation in power output from the heating pad. A more consistent power source would improve the data The trend line from the data plotted should allow you to combine sleeping bags and predict the effective temperature rating