I think the reviewer had been given mis-information about the bag. The bag is excellent even down to freezing. But is NOT specified by the manufacurer as a cold weather bag. They rate it at 40F (which is what the other reviewer guessed would be believable temp. The ratings can be seen below - http://www.phdesigns.co.uk/minimbs.html http://www.phdesigns.co.uk/index.php?cPath=26_60 I don't what advert was saying that it was good down to 20F, but it certainly isn't the manufacturer's opinion! Full review
Perhaps a weird impulse buy... but this is the second extremely light weight bag I've had of uncertain manufacture. The first one never warmed me either but allowed ultra light camping until it self destructed from poor construction. This one however is well made and I paid for it... but the hand writen ad saying it was rated at 20 degrees F. is a total mistake. Maybe 40 at the least (or is the most). No zipper... surprizingly not difficult to deal with. Minimalist for sure but cozy .... in your… Full review
Peter Hutchinson was formerly the founder of Mountain Equipment. PHD makes down Sleeping Bags, down jackets, and mountaineering clothing in England.