I have had this sleeping bag for a few weeks now and it's great. I have not been able to test it to the -20 F that the bag can handle but I have taken it to about 35-40 F and it was super warm, pretty much to the point where I had to unzip the bag a big at the feet to let some heat escape. This bag is great otherwise. Super comfortable and very light and the stuff sac/compression sack is very convenient for packing the bag even smaller than it is. If your looking for a warm durable sleeping bag definitely check this one out.