I'm very curious if it makes a difference, too. Aluminum or other similar surfaces (mylar emergency blankets for example) retain heat best when not in contact with the skin or anything else. It is all about radiated heat rather than conducted heat. Aluminum will conduct heat really well, but it doesn't radiate it so well. It reflects it. In other words, as long as there is no contact, aluminum should do a great job retaining body heat. With contact, though, it should actually do the opposite. That is why you put the foil side of insulation on the outside under siding. It reflects the heat in all the little air pockets in the foam. If you put it against the boards, it will conduct heat from the house. I believe their claim is that the conductive material somehow holds the heat it absorbs rather than passing it along to other layers.
Columbia also makes base layers and outer layers with "silver dots". I have a jacket with them and I am not impressed. I would say the jacket is a medium weight jacket so it's not an extreme weather jacket and I wouldn't buy it again. I prefer my Eddie Bauer goose down jacket.
I have not tryed the long underwear with the silver, I do own the Under armour long underwear pant/shirts, they go on under all your cloths and are super tight, no wind touches your skin and there is a huge difference in temp using them.
There is a lot of technology going into clothing these days. I wear some of the older tech stuff(10 years old). It does help. But in the end, our mom's were right. Layering is where it's at.
I thought the introduction of silver was more for anti-bacterial properties and to reduce stink when you have been wearing them for awhile. Seems like my son got a pair of silver infused underwear for a Boundary Waters trip so he could wear one pair for a month or so.
Silk for cold days when you have to be indoors.
Polyprop works well for when I am outdoors in temps hovering around the freezing mark and slightly below.
Silk and polyprop when temps drop to around zero
Silk, polyprop and snow pants when temps drop below zero.
I like Under Armor products. I don't think they are total hype. I have a few garments and they are several years old and show no signs of wearing out. I also think North Face is pretty good, though I don't own any.
Disclaimer: I have a low body fat % and tend to be colder than others. The above for me is when I am not moving much. If I am out for a run, I wear way less.
That's just it. It would be hard to tell if the dots make a difference to me on their base layer because of how well their stuff works without the dots. In Indiana, I don't think there is a real reason to pay extra (not sure if the cost is actually higher) for the dots since their regular stuff works so well. Still, the science of whether the dots work intrigues me.
Thanks, Mcolson181, for that on Columbia. That was something else I had been looking at and wondering about.
Biggest concern I have realized is to not get too warm and start sweating, then your in trouble, regulate and stay warm but do not let yourself break a sweat. As a background comment I work outside all the time, all year round and layers, wind and water protection are key in winter.
I was trying to remember "Duofold" in the previous cold weather clothing thread. It's great stuff. The only better I have is my two pairs of (very expensive) Nomex III long underwear from Massif Mountain. The current military cold climate "system" has 7 layers, I believe, and "underlayers" comprise two or three of those layers.