Good thermal underwear

Q. Hello Gear Guy, My son will be attending a Freeze-O-Ree next month. We need to get some good thermal underwear for 30-40 degree temps. What can you recommend?
— Wanda the Scout mom, Phenix City, Ala.

A. There are two basic types of thermal underwear: those made with synthetic fabrics and those made with wool. Both types of long underwear come in three basic weights including lightweight, midweight and expedition weight. Some brands also offer a couple more weights on either end of the thickness spectrum. I’d say for your son’s needs he should stick right there in the middle with midweight long underwear. Unless he’s very cold-natured midweight should take care of the 30-40 degree temps he’ll be experiencing and this thickness will be most useful and versatile throughout the year. Also, although there are lots of different styles, I’d recommend a simple crewneck long-sleeve top and basic pull-on bottoms — that style is most affordable and, in my experience, the fewer zippers and snaps the better.

Now, onto synthetic versus wool. Let me start by saying both types do an excellent job of keeping you warm and wicking sweat away from your body to keep you dry. Back in the day, wool was the standard for long underwear and in the past five years or so it’s really gotten popular again. Though it is more expensive (about twice as much as synthetic), wool doesn’t retain odors, is eco-friendly, and some say the natural fibers regulate your body temperature better — though I’m not sure on that. If you go the wool route be sure to choose Merino wool as it won’t be itchy. A few good brands to consider include Icebreaker and Smartwool. While I love wool (and use it myself often), I’d say for your growing Scout, synthetic would be a better, more affordable choice. Synthetic long underwear will keep you warm like wool and can wick and dry more quickly at times, making it a great choice for aerobic activities where you’ll be sweating a lot. Though most brands have worked to address the stink-ability of synthetic, it still holds odors more than wool. While synthetic fibers aren’t particularly flammable, they will melt to your skin in a fire so keep that in mind. In the end, synthetic is an affordable, great performing option that’ll keep your Scout warm and dry. All major outdoor brands make similar products, but a couple of the best values are:

• REI Midweight MTS Long-Sleeve Crew and Bottoms ($30 each; www.rei.com)
• LL Bean Polartec Power Dry Midweight Crewneck and pants ($32.50 and $29.50; www.llbean.com)
• Cabela’s MTP Polartec Medium-Weight Crew Top and Drawers ($25-$30 each; www.cabelas.com)