Spending 21 years worth in the Army I can tell you the secret to keeping warm isn't the bag. First you need large caloric intake just prior to calling it a night. If you don't have this the body isn't generating any heat so the bag has no heat to keep in. Second, you shouldn't be wearing clothes in the bag only your shorts, a beenie and socks. The head and feet is where over 80% of your bodies heat escapes. Next the bag, get one with good draft tubes, spindrift tubes around the shoulder and a good hood that cinches down tight. The best brand out there is Western Mountaineering. Have a good pad underneath. I would suggest the alaskin expedition pad from Cabelos but it just delaminated on me on my last trip to The Maze. I myself finally after 47 years of doing without bought a blackcat tent heater on my last trip. The last night in the Swell the wind was howling about 40mph it was 27 degrees out and I ended up sleeping on top of my bag. Last, if you bought a cheap tent that builds up condensation you're more than likely going to be miserable anyway.