The heat tech stuff is great this time of the year or early spring. But you will need an actual winter coat. February routinely gets -20+ with wind chill

I have a pair of LLBean slippers that were gifted to me. I love them. I just happened to look them up recently to see about getting another pair and almost spit my water out when I saw they were $90. I love them but they're not worth me spending $90 of my own money.