I use the Ameristep Dog House Blinds, have 3 of them, non insulated. Have never seen a need for insulation. I've spent time in them in all sorts of temps and weather. They will get condensation and frost on the inside during some humidity and weather conditions, however that is a lack of heat source issue not because the fabric is not insulated. The only problem I had in cold weather with moisture is the zippers freezing up, and a bear made me a new door and window in one as well. My oldest one is about 7 years old with no issues. Two have been set up and left out for several months at a time, I have had to gently ease them out of the snow several times to bring them in for the winter as they have been frozen to the ground.
My suggestion is to buy the blind that suits your needs, and put a good quiet swivel chair in it, dress warm then put in the time.