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By the Numbers is a new Backpacking Light column from Stephen Seeber. In this space, Stephen turns a critical eye towards fabrics and materials by testing for claims, degradation, and more. 


I am using a smaller pack now for day hikes. I decided I needed to replace the fleece midlayer that I carry with something warmer, lighter, and more compact. From one of my prior studies (study link), I learned that Patagonia PlumaFill had the best warmth-to-weight ratios of the synthetic insulations that I tested. I felt a Patagonia Micro Puff might be the replacement garment that met my needs. I decided that I would prefer to purchase a Worn Wear jacket to save money. Patagonia Worn Wear sells used and reconditioned Patagonia garments at a substantially lower price than the new products. I had not purchased a Worn Wear garment before, so I thought I would order a reconditioned Patagonia Micro Puff and then see how it compared with a new Micro Puff in laboratory conditions.

Fleece Evaluation

I started by determining the basic characteristics of the two fleeces that I carried on hikes. The results are listed below:

Fleece TypeBrandJacket Weight (grams)Measured R-Value*Measured Clo-Value**Grams/R
HeavyColumbia458 (16 oz)0.430.491060
LightMarmot302 (10.6 oz)0.300.341013

*R-value: quantifies the ability of a material to resist the flow of heat

**Clo-value: Quantifies the ability of a fabric or garment to resist the flow of heat.

Thermal resistance testing was conducted using my permeation kettles and my Flir A655SC thermal imager.

You can read about how I test R-values here.

The images below show the thermal tests of each fleece jacket in comparison with the new Micro Puff.

Left: new Patagonia Micro Puff. Right: Heavy Fleece
Left: new Patagonia Micro Puff. Right: light fleece.

Patagonia Micro Puff Insulation Evaluation

I purchased a medium-sized Patagonia Worn Wear Micro Puff. They accidentally sent me an extra-large. Then I purchased a new large-sized Patagonia Micro Puff for comparison.

The thermal image produced by the test is shown below:

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