The best thermal underwear
One of the most common pieces of advice for dressing in colder weather is the importance of layering. Wearing several layers of thin clothing traps more insulating air than wearing a heavy sweater and a snow jacket. The first layer should be a quality pair of thermal underwear. Thermal underwear features a thick but breathable ribbed design for additional insulation and construction that wicks away moisture, dries quickly, and may even neutralize odors.
When shopping for thermal underwear, it's important to consider whether to buy a complete set or just the top or bottom. Some people prefer to wear a thermal underwear top as part of a layered look or even by itself as casual wear. Others like to improve circulation and reduce cramping in their legs by wearing thermal leggings. A thermal underwear set can also be used as sleepwear instead of thin pajamas.
To learn more, keep reading our buying guide. At the top of our list is Thermajohn's Men's Ultra-Soft Thermal Underwear Set, a complete set of men's thermal underwear that has the snug fit of spandex and great wicking capability.
Considerations when choosing thermal underwear
Much like flannel shirts or pajamas, thermal underwear is often categorized by weight. People in mild climates may only need an ultra-light or microweight set to boost body heat. Those in slightly cooler regions should opt for a lightweight set. If winter conditions are moderately cold for months, then a midweight is ideal. Heavyweight thermal underwear should be worn during frigid conditions such as winter camping trips or hikes.
The materials used in a thermal underwear set can make a difference in terms of durability and comfort. Cotton is a less expensive option, and it does a decent job of insulating the body in moderately cold weather. However, cotton does retain moisture, so it is better suited for situations where minimal physical exertion is anticipated. Synthetic blends such as nylon, polyester, and spandex are still relatively inexpensive, but do a better job of wicking moisture and reducing odors than cotton.
For those who require a heavier layer of insulation, wool is a good choice, especially Merino wool. Wool is the original material of choice for thermal underwear and provides a high level of natural insulation and strong wicking. However, it can be somewhat scratchy on the skin.
For the ultimate feel of luxury, there's silk-based thermal underwear. It may not be as thick or insulating as wool or a polyester/spandex blend, but silk is exceptionally comfortable and can be treated to improve wicking and odor control. Silk is also very thin, which may reduce bulk when layering clothing.
Durability and ease of use
The good news is that regardless of material, most thermal underwear is considered machine washable. The bad news is that it may not always be machine dryable. Pre-shrunk cotton may survive the process, along with some synthetic blends, but wool or silk-based brands need to be air-dried between wearings to avoid shrinkage and fading. When shopping for thermal underwear, it is important to consult the laundering information found on the tag or in the product description.
Prices for thermal underwear can vary widely, depending on the number of pieces in the set and their materials. A basic cotton thermal top or legging can cost as little as $10, but $20 to $30 is a good benchmark. Higher-end sets made from wool or polyester/spandex blends can cost $100 or more.
Q. What advantages does thermal underwear offer over regular underwear?
A. Thermal underwear is designed to retain body heat more efficiently than traditional underwear. It also wicks away sweat, and some brands incorporate odor-killing agents into the material.
Q. Can I wear thermal underwear year-round?
A. Thermal underwear is typically worn as a base for cold weather layering, but many tops are stylish enough to be worn as casual shirts during other months. A complete set of thermal underwear can also function as sleepwear.
Thermal underwear we recommend
Best of the best: Thermajohn's Men's Ultra Soft Thermal Underwear Set
Our take: For those who prefer to dress in layers for cold weather conditions, this two-piece long john set makes an excellent first layer without adding bulk.
What we like: Uses a stretchable polyester/spandex blend. Available in four colors: black, gray, navy, and white. Wicks away moisture and dries quickly. Very thin profile; does not add bulk to outer clothing.
What we dislike: Darker colors can bleed dye on clothes or furniture. Material is thinner than expected, not as heat-retaining as other brands.
Best bang for your buck: Duofold's Men's Mid-Weight Wicking Thermal Pant
Our take: This pair of thermal pants features the comfort and wicking ability of cotton with the chafe-free fit of polyester or spandex.
What we like: Two-layer cotton construction. Smooth seams resist chafing. Rib-knit cuffs prevent ride-up. Can be worn as a base layer or by itself as nightwear.
What we dislike: Sizes tend to run larger than expected. Some complaints of a high-waisted fit.
Choice 3: uYES' Women's Thermal Underwear Set
Our take: The combination of fleece and a poly/spandex blend means this two-piece thermal underwear set feels like comfortable pajamas at night or a warm bodysuit during the day.
What we like: Fleece-lined top and bottom are very comfortable. Can function as a base layer or standalone sleep set. Available in a wide array of colors. Polyester/spandex construction is very stretchy but not constricting.
What we dislike: Sizing is a common complaint; the pants may be a true fit, but the top tends to run small. Dye may not be completely set upon arrival.
Michael Pollick is a writer for BestReviews. BestReviews is a product review company with a singular mission: to help simplify your purchasing decisions and save you time and money. BestReviews never accepts free products from manufacturers and purchases every product it reviews with its own funds.
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