Tester Information
Tester Name: Will Rietveld
E-mail: mailto:willjanet@sisna.com
Gender: M
Age: 60
Height: 6 ft (183 cm)
Weight: 170 lbs (77.3 kg)
Location: Durango, Colorado, USA
Backpacking Background: 46 years of hiking and backpacking in the mountains and deserts of southwest Colorado, southeast Utah, New Mexico, and Arizona. I have also made numerous trips in Wyoming, Montana, Minnesota, Wisconsin, and upper Michigan. I have been a lightweight backpacker for many years, and an ultralight backpacker for 4 years. I have been retired for 6 years and backpack frequently. My wife and I present workshops on ultralight backpacking in the local area and have developed a website called “Southwest Ultralight Backpacking.” The URL is: http://users.sisna.com/swultralight/.

Manufacturer Information
Name: Hot Chillys
Website: http://hotchillys.com/

Product Information
Product Tested: Hot Chillys Bio-Silver Bi-Ply Outdoor Baselayer
Style, Color, and Size: #2233 Men’s Zip Top, White, Large
Year of Manufacture: 2003
Fabric Description: The Bi-Ply knit fabric has a soft feel. The outer layer is 100% MTF (Moisture Transfer Fibers) microfiber polyester, and the inner layer is 75% microfiber polyester with 25% Bio-Silver. The fabric has moderate stretch in both directions and is smooth on both sides, allowing other clothing to easily slide over it.
Weight Listed: Not provided.
Weight as Delivered: 10.9 oz (309 g).

Product Features
According to product information, the top is designed with an anatomical relaxed fit, allowing freedom of movement without bagging. It has a mock turtleneck style collar with a 9 in (22.9 cm) zipper and distinctive red chili pepper zipper pull tab. Flat seam construction is strong and eliminates abrasion. The Bi-Ply knit places imbedded silver yarns combined with MTF polyester next to the skin to conduct heat, rapidly transport moisture, and minimize bacterial buildup and odor. The top has a “Hot Chillys Warmth Factor” of 8, and an Ultraviolet Protection Factor of 20+.

Product Arrival and Condition
The Hot Chillys top arrived in perfect condition via UPS on October 13, 2003. The top was packaged in an attractive 3.75 in x 3.75 in x 9.5 in (9.5 cm x 9.5 cm x 24.1 cm) box featuring an outdoor scene and printed information on the fabric, construction, and features. A Bio-Silver logo explains its benefits. A flow diagram shows how the garment wicks moisture away from the skin while trapping warm air. Other symbols indicate the garment’s ultraviolet protection factor and warmth factor.

Although the attractive box makes an excellent presentation of the product, the information printed on the box does not communicate as well as it could. Specifically:

Under “Construction”, the first bullet states “Tri-component bi-ply knit for warmth and comfort. The “tri and bi” parts are a mouthful and I can’t say I truly understand what is meant by tri-component. There are 4 bullets. The first, third and fourth are parallel while the second is constructed differently. The first 2 bullets both refer to comfort and performance. Perhaps they could be combined into one statement or, if kept as two items, have one refer to comfort and the other to performance.
In the flow diagram, I would recommend that the 3 performance features be changed to parallel construction, e.g., moves moisture, traps warm air, and repels wind and elements.
Nowhere does it say what MTF stands for.
The first 2 cells of the Bio-Silver logo seem to say the same thing.
The anti-microbial properties of the product are not readily apparent from looking at the box. Bio-Silver” does not necessarily speak for itself. It takes some examination to understand that Bio-Silver means anti-microbial. Maybe it’s intended to be that way.
Despite the questions I raise about the printed information, the box is visually very appealing. I was compelled to read and re-read the information to try to “get it.” I feel that the presentation of the product could be even better if the printed information were clearer.

Initial Impressions and Comments
After wearing the top around the house for a few days and on a short hike, I can make the following comments:

The top fits me very well. It has an “anatomical relaxed fit”, i.e., it fits close to my body but is not snug. The shoulders are right on. My arms are a little longer than normal, yet the sleeve length is just right. The body length is about 6 in (15.2 cm) below my waist.
The top is quite stylish and could be worn in casual social situations for an “outdoorsy” look.
The top could function equally well as an outdoor base layer or as a hiking top. These are the applications that I am most interested in.
I found the top to be quite comfortable on a short hike, wearing it as a hiking top. The temperature was about 60 F (16 C) under sunny and breezy conditions.
After wearing it off and on for three days I noticed some pilling on the sleeves, seam side, from the elbows down to the wrists.

Test Plan
Locations and Conditions—As the season progresses into the fall and winter, I will have many opportunities to evaluate the Hot Chillys top both as a single layer hiking top and as a base layer. I will test it in a variety of climate situations in the Southwest. First, I plan to wear it continuously while camping and elk hunting for 10 days (which will be a good test of its anti-microbial properties). Next, I should be able to do a few more short backpacks and day hikes in the high mountains before I get snowed out, so I will be able to test the top at high elevations (10,000-4,000 ft/3048-4267 m) where it can be intense sun and warm during the day, cold at night, and possibly windy. In November, I will be shifting to hiking in the desert and canyon country of New Mexico, Arizona, and Utah where elevations will be lower (5000-6500 ft/1524-1829 m) and conditions will vary tremendously. Outings will consist of backpacking and car camping/day hiking. Daytime temperatures are usually warm (40-60 F/4-16 C) and nights are cold (10-35 F/-12-2 C). It can be very windy at times when cold fronts move through, and snow showers are likely. I will also be doing some snow sports in the mountains, consisting of cross-country skiing and snowshoeing as day trips. Thus, the Hot Chillys top will get a thorough evaluation under a wide variety of conditions during the next six months.

Plan—I chose to evaluate the zip-neck top in white because I believe this combination will give the most versatility as a single layer hiking top. A black top can absorb a lot of radiant heat in the Southwest. That would be just fine on cold days, but on sunny days (the more usual situation) the black color would limit the comfort range of the top and the situations and seasons where it would be comfortable. Opening the zipper will provide more ventilation and temperature adjustment when needed.

On multi-day trips, the Hot Chillys top will stay on for the entire trip. During the day it will be a single-layer hiking top (weather conditions permitting), and at night it will be a base layer with insulation layers over it. There will be high exertion activities in cold weather when I will wear only a shell layer over the Hot Chillys top to deflect wind, rain, or snow. At least once I will wear the Hot Chillys top 24/7 to evaluate the limit of its ability to suppress smells.

On each trip I will take a thermometer with me to measure the comfort range of the Hot Chillys top, i.e., the temperatures where the top is feeling either too hot or too cold. In my notes for each trip, I will record the following data in relation to my comfort level wearing the Hot Chillys top: 1) temperatures, 2) estimated wind speed, 3) estimated humidity, 4) altitude, 5) precipitation (including what form), 6) how the Hot Chillys top was worn (single layer or base layer), 7) my exertion level, 8) how much I sweated, 9) how long it took for the top to dry out when I stopped exerting, 10) how chilled I felt (when stopped) because of moisture in the top, and 11) how chilled I felt from wind.

Factors Evaluated—The specific factors I will evaluate the Hot Chillys top for are:

How comfortable is the top to wear? Does it fit well (tightness/looseness, sleeve length, body length) Is it non-binding? Does the zipper rub against my skin? Is the collar comfortable when used alone or as an under layer. Does other clothing slip over it easily?
How well does the top perform as a single-layer hiking and backpacking top? Is it sufficiently warm for cool weather hiking? Is it comfortable over a wide temperature range? Does it wick away moisture and dry quickly? Is it adequately wind resistant?
How well does the top perform as a base layer under other clothing? Does it readily wick moisture away from my skin and dry quickly? Does it hold body heat well?
How well does the top perform in combination with other performance clothing? For example, how well does it perform under a water-repellent/breathable shell (like EPIC) in rainy weather and moderate to high exertion?
How effective is the “Bio-Silver” feature in reducing or eliminating odors? I have polypropylene and Capeline shirts I can compare it to. Are there limits to its anti-odor capacity, and if so what are the limits? Does washing completely remove odors? Does washing affect the longevity of this feature?
How durable is the top? On my various trips, I will be doing a fair amount of bushwhacking and will give it a good test to see if it snags very readily or not. Does the material pill in wear zones, e.g., under the arms? Given the white color, do stains wash out? What is its life span likely to be under the conditions I am using it?
What is its utility for ultralight backpacking? How does its performance compare to other hiking tops I have (Patagonia, Wickers). How well does it balance features, performance, and light weight?

Expectations for the Hot Chillys Bio-Silver Top
By the end of the test, I should be able to support or refute the following expectations (stated as hypotheses):

The top will be comfortable to wear in terms of being non-binding and non-abrasive.
The top will be sufficiently durable as a single-layer hiking and backpacking top and will require little or no maintenance or repair (i.e. minimal snags, no need for de-pilling, no seams unraveling).
The top will be odor-free or low odor, thanks to the silver strands embedded in the fabric.
The white color (my choice) and zip neck will allow it to function as a hiking top under a fairly broad temperature range.
The top by itself will have a significant amount of wind resistance.
The top as a single layer or base layer will effectively wick away moisture and dry quickly, to avoid chilling.
The top as a single layer will retain body heat and have a significant warmth level.

I will evaluate the Hot Chillys Bio-Silver Bi-Ply top with the above expectations in mind, over a wide range of terrain and weather conditions. During each trip I will record data and notes and after each trip I will document how well the top met my expectations and needs. After six months of use I expect to have plenty of documentation and clear opinions on how well the top met the above expectations. Based on the data, the above hypotheses will be either accepted or rejected in my Long-Term Report.

I would like to thank Hot Chillys and the BackpackGearTest group for selecting me to participate in this test.

Will Rietveld

Read more reviews of Hot Chillys gear
Read more gear reviews by Will Rietveld

Initial Report

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