Long-Term Report:
Duofold Varitherm Silkweight Base Layers

Summary
I wore the Duofold Varitherm Silkweight base layers a total of 61 days in a wide variety of activities over a four-month test period, and found them to be a top-notch product in terms of comfort and performance. They effectively wicked moisture away and maintained dryness in a wide variety of outdoor activities, equivalent to the performance of silkweight polyester base layers from other manufactures. Imbedded silver threads in the fabric effectively inhibited the growth of bacteria, resulting in low odor, even after wearing them continuously for ten days. The only problem I had was the sizing of the top tended to run small. They are a good value at $25 for top or bottom.

Product Description
From product packaging: “Duofold Varitherm High Performance Base Layer defines the standard for high activity thermal protection and moisture management. Whether you ski, ride or ice climb, Varitherm base layer will keep you warm and dry. Offered in a variety of weights and fabrics, Varitherm’s performance features are permanent and will last the life of the garment.

Silk Weight garments provide lightweight protection, perfect for layering or by themselves in milder climates. Silver-based anti-microbial yarns help prevent odor by inhibiting the growth of bacteria on garments so they stay fresh.

Varitherm Fabrics wick moisture away from the skin for quick evaporation, keeping you warm, dry and comfortable.”

Test Locations and Conditions
Test Period—Mid-December 2005 to mid-April 2006.

Test Locations—Southwestern US (Colorado, Utah, New Mexico, and Arizona).

Testing Conditions—Testing terrains consisted of: badlands desert, canyon country, forests, and high elevation alpine country. Extreme conditions included: snow storms, strong winds, dust/rain storms, intense sun, low temperatures, and high elevations with strong UV radiation. Temperatures ranged from 15 to 75 F (-9 to 24 C), elevations ranged from 4,000 to 12,000 feet (1219 to 3658 m).

How the Base Layers Were Tested—I wore the base layers with different clothing systems, outdoor activities, and activity levels. I wore them by themselves in a sleeping system and as a base layer with other clothing layered over them. I wore the top by itself when the ambient temperature was warm enough. However, because of the winter/early spring test period, most of the time I wore additional layers over the Varitherm Silkweight Base Layers for extra warmth.  

Amount of Use and Activities—The Duofold Silkweight Base Layers were my primary base layers during the four-month test period. I wore them on a total of 46 trips totaling 61 days in the activities listed below. In addition, I wore the base layers in camp while winter camping a total of 27 days, and slept in them in a sleeping bag a total of 26 nights. I also wore them to watch a winter parade and to pick up trash along our adopted road section.

Measurements and Data—After each trip I recorded the following data in relation to my comfort in the Duofold Varitherm Silkweight Base Layers: 1) temperature, 2) estimated wind speed, 3) estimated humidity, 4) altitude, 5) precipitation (including what form), 6) clothing system, 7) clothing worn over the base layers, and 8) how well they performed in terms of warmth, utility, and comfort.

Factors Evaluated
Following are the specific factors on which I evaluated the Duofold Varitherm Silkweight Base Layers. In this Long-Term Report, I provide information based on four months of testing.

Fabric—100% polyester. The fabric has a lot of horizontal stretch and some vertical stretch. It is tightly woven with a fine vertical pattern (see photo). The fabric includes fine silver threads (not visible) for microbial suppression.

Construction and Quality—Excellent. All seams are flat to minimize abrasion.

Sizing and Fit—The sizing of the top runs a little small and the fit is trim. A size large shirt is normally a good fit for me, but the size large Duofold Varitherm Silkweight top was trim in the body, and the sleeves barely extended to my wrists. The tail extended below my waist about 6 in (15 cm) when tucked in, which was adequate. For me, a size large-tall top would be a better fit to provide enough length in the body and arms. The size large bottom was a good fit; it was loose in the body and legs and had enough length to cover my ankles.

Features—The top has a 2 in (5 cm) dropped tail; the bottom has an elastic waistband and a fly.

Measurements—Top (size Large): body length is 27 in (69 cm) in front and 29 in (74 cm) in back, chest is 42 in (107 cm), sleeve length is 32 in (81 cm). Bottom (size Large): length is 41 in (104 cm), inseam is 29 in (74 cm), waist girth relaxed is 30 in (76 cm), and waist girth expanded is 48 in (122 cm). All measurements are relaxed unless stated otherwise.

Articulation—The articulation of the top is good but not excellent. With my arms raised above my head, the sleeves pull back from my wrists about 1 in (2.5 cm); bending over with my arms crossed, the sleeves pull away from my wrists about 2 in (5 cm). The bottom fits looser and does not bind in the crotch area or thighs when I raise one leg.

Usability—The Duofold Varitherm Silkweight Base Layers have a smooth surface, so it is easy to don other clothing over them. For hiking in cool weather I frequently wore another base layer over the Varitherm top. In camp I wore additional insulation layers over that. I was able to wear the Varitherm top as a single layer while vigorously hiking at temperatures above about 50 F (10 C). The same was not true for the bottom; I could not wear it while hiking unless the temperature was below freezing (32 F/0 C). I mainly wore the bottom for less strenuous activities like ice fishing and in camp. I typically wore both base layers (and other layers as well) while sleeping in a sleeping bag, to keep my bag clean and to extend its warmth.

Comfort—The Varitherm Silkweight Base Layers felt soft and warm against my skin. I wore the top over a broad temperature range (with other layers over it as necessary), ranging from 15 to 75 F (-9 to 24 C), and found it to be quite comfortable. It provides a surprising amount of warmth for its thickness and weight. In warmer temperatures I definitely sweated in it, especially behind my pack, but it always dried out quickly after I stopped.

Performance—For wicking moisture away from my skin, I found the Varitherm base layers to be as effective as other polyester base layers I have tried, like Patagonia Capeline. At low exertion levels and temperatures the base layer remained dry, but at high exertion levels and temperatures they definitely get wet with sweat, especially behind my pack. After I stopped they dried out quickly in about 10-15 minutes. At cold temperatures (below freezing) and high exertion I wore the Varitherm top under another base layer and a wool shirt (Ibex Scout Shirt). At cool temperatures  around 30 to 45 F (-1 to 7 C) and high exertion, I was comfortable and fairly dry wearing the Varitherm top under a hiking shirt. With high exertion at temperatures above about 50 F (10 C) I was comfortable wearing only the Varitherm top, and it did an exceptional job of wicking moisture to keep me dry.

Odor Management—The Varitherm Silkweight Base Layers resist odors very well. On four extended trips I wore the base layers continuously for up to ten days. When I got home a sniff test revealed a moderate body odor, but no foul smell reminiscent of polypropylene underwear. In my opinion, the Varitherm’s anti-microbial feature is one of its strongest attributes.

Weight—At about 10 oz (283 g) for the top and bottom, the Varitherm Silkweight Base Layers are quite light. They provide a lot of warmth and utility for their weight, and are suitable for ultralight summer backpacking.

Durability—After 61 days of wear the base layers show no signs of pilling or wear. The bottom has one snag of unknown origin.

Versatility—I found the Duofold Varitherm Base Layers appropriate for a variety of
outdoor activities in cold weather.

Value—At $25 each for the Silkweight Varitherm top and bottom, they are a good value compared to Patagonia Silkweight Capilene at about $34 each, and Microweight Smartwool at $55 each.

Cleaning—Washing instructions are: “Machine wash cold with like colors, do not bleach, no fabric softener, tumble dry low, do not iron”. I machine washed the base layers about ten times in a wash machine (warm wash/cold rinse) and hung them on a hanger to dry. I had no problems with shrinkage or fabric deterioration.

Acknowledgement
I would like to thank Duofold and the BackpackGearTest Group for selecting me to participate in this test.

Will Rietveld