Is it keep me warm under zero?
81961
If you mean, will it keep you warm when the temperature is below freezing, the answer is yes. Wear them under your regular clothing and use appropriate cold weather gear when outdoors.
1532130
Actually hard to answer! I have noticed that on a cool night, it keeps me comfortably warm. Yet on warm nights I don't get overly warm! It acts like it adjusts. I really do like it!
877776
Hard to answer. It is warm to the point I very seldom use the heat part and I am old and Thin. Best I can do.
129888
We used them in the Andes and it got below zero. Sleeping bags kept us warm!
752360
I'm not sure if you can regard the "low" setting as "cool", but it is the one I use frequently which feels warm. It has two settings, Lo and Hi
20290
I find it as warm as a medium fill down parka, but not quite as warm as a really high fill sub arctic rated down parka. It serves me well pn MOST winter days, all but the most frigid (below zero )
409108
I don't ski but I can tell you they kept me warm on a day when we had wind chills of 10 below zero and I was working outside. Does that help?
45290
No, not too warm, wear it under in very cold weather; wear it under in cool weather, like layers.
640027
I do not know. It is warm. It served its purpose. I wouldnt recommend it though.
1507050
I think it will keep you warm not sure about fit for physical activity though. The heat reflective technology is very effective.
20287
Not as warm but if you put on a sweater and undershirt it will keep you nicely. If you are outside alot in 20 degree weather you would need to put on an extra layer for sure. I bought a polar fleece hood that I wear with my coat and if I have that on I am just perfect with warmth. the hood is really just a wind, snow and rain blocker. My other down coat had a very warm hood and I did miss that warmth, but when I started wearing the fleece hood I know longer missed it and I could see more easily.
3680
This doesn't zip inside the parka, it's meant to be worn as the layer right underneath. It's a high-quality fleece - under a ecws parka it'll keep you warm.
1345916
My first use of this bag was on a night that dipped to 40 degrees. If I completely covered myself (hood up and tight) I was actually a little too warm. My feet were chilly all night though regardless - wish I had worm wool socks that night.
535448
Yes, you can use it to keep things warm. It has an infinite control that goes to very low heat.
910955
I am in a desert, so cool is never really an option. I can say my blanket makes me sweat before this pad ever does. I believe if you are in a comfortable tempurature that you will not sweat any more than usual.
386215
"Warm enough" depends on the person. That said, I wear mine from +15F to +50F and I am perfectly warm. Below freezing they keep me warm only if I am actively cycling. If I stopped for more than a quick snack (15 minutes) I would be a bit cold.
1092288
No, I do not feel hotter but a little warmer. It gives a softer feel when sleeping.