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Introduction: Polyester Batting and Polyester Fleece are two popular types of insulation for clothing and sleeping bags. Fleece is a stronger material but holds less air, so is convenient for stitching garments, whereas batting is more suitable as a filling for sleeping bags, combined with a stitched cover. We would expect that batting is a better insulator because it traps more air. Let's see.
Method: I took two flasks of boiling water ( 0.5 kg water ) and wrapped one with batting and the other with fleece. I waited one hour and measured the temperature. I repeated the experiment twice to avoid errors. Here are the results:
|Batting ( Exp 1 )||Fleece ( Exp 1 )||Batting ( Exp 2 )||Fleece ( Exp 2 )|
|Area Density ( kg / m2 )||0.283||0.192||0.281||0.198|
|Temperature Loss ( Kelvin per hour from boiling )||20||29||21||26|
|Insulation Value ( Inverse of Previous Row, Proxy for R value )||0.050||0.034||0.047||0.038|
|Insulation Value per Area Density||0.176||0.177||0.167||0.191|
Conclusion: Temperature loss is proportional to the energy lost by the material and is inversely related to the R value of the material. According to this quick experiment, batting and fleece are almost the same. So fleece, with its other advantages, is the winner.