Do your due diligence before buying a sleeping bag. There are light weight down bags that as long as they are dry they're warm and easy to pack but as soon as the down collects moisture from your body or any outside source their insulation value can go down to around zero depending on the degree of dampness.
Synthetic bags are not as light nor compressible as down, are less expensive and may work well for a year or two. They may last longer if you keep stored out of their stuff sack and hang them up or lay them flat with none of the bag compressed in any way (which I find inconvenient). If they get wet, they are slow to dry and have a greatly reduced insulation valve.
My suggestion is to go to Wiggys.com and examine his sleeping bags. Wiggy's temperature ratings on his bags are very conservative compared to other manufacturers. His bags will keep you warm even if they get wet unlike any other bag on the market. Wiggy's bags can be stored in their stuff sacks, even compression bags for years without losing their insulation value. That's why you'll find Wiggy's vacuum packed survival suits attached to the underside of all US fighter jet ejection seats. Wiggy's bags are machine washable too. When you get home from your trip, throw it in the washing machine and dryer and it's good to go on the next hunt. Wiggy's has a 0 degree bag on sale now:
https://www.wiggys.com/specials/sale-super-light-marpat-select-color-sleeping-bags/
If you're car camping and your bag for some reason gets wet, it can be an inconvenience and maybe you'll have to spend the night in a motel until you get everything dried out. If you're ever going to do a drop hunt, your choice of bag may save your life should things go wrong and your bag gets wet. Below is a letter from a Wiggy's customer who had things go real bad on a hunt.
Jerry,
Well, I never thought I’d be writing a letter and thanking you for saving my life, but well, that’s just what this note is for. I went on a caribou hunting trip with my twelve year old son over the past weekend, flying out on Friday to a remote wilderness area about two hundred miles from Anchorage, Alaska. We were in a PA-18 Supercub floatplane. On Sunday afternoon, during the takeoff roll the aircraft flipped and went inverted, literally upside down and partially buried in the bottom of the lake. At the time, the winds were probably 10 to 15 mph, with some occasional gusts higher than that. After the accident they increased continuously over the next several hours. By nightfall they were gusting to at least forty. The temperatures were in the fifties but were dropping rapidly. The sky was clear, and the terrain was flat and open without any trees.
When we flipped, we, and everything we owned, were instantly soaked. Totally—submerged in fact. My son and I were wearing inflatable CO2 survival vests, and synthetic clothing with hip boots--all typical attire for Alaskan bush flying. After we successfully extracted ourselves from the upside down airplane, I took the time to get as much stuff out of it as I could. I wanted my Wiggy's sleeping bags, as I knew if we had any chance to survive, they would be key. It took me 30 minutes to get them—I had to cut a hole into the part of the aircraft that was still out of the water and push them forward where I could swim down and grab them from inside. We both had the Super Light FTRSS bags, in their stuff sacks. They were drenched; literally, the pressure from being held that long under water had been enough to soak them pretty thoroughly. Still, they were the only things we had. I tried to find the tent without success, and finally gave up looking for it.
We swam to shore, and my son and I were both hypothermic, him more so than me. We dove behind some small bushes, which was the only visible cover within miles. The bushes didn't completely block the wind, but they helped a lot. The ground was boggy, and wet, but to go to higher ground would have exposed us to the full force of the wind. There was no firewood or any other large trees—just miles of rolling tundra typical of caribou habitat. The picture I've attached captures the bleakness of the place pretty well, I think. It was taken 24 hours after the accident. Anyway, after we got to shore the real survival had just begun. My son wasn't talking much at this point, and I knew his situation was more desperate than mine. Since we were both shivering so badly, we were losing coordination, I recognized the symptoms of hypothermia and took the only action open to me. Like something out of a survival manual, we stripped off the wet clothing and got into one of your sleeping bags. I would have mated them together but I was too cold to try and change the zippers, so we just unzipped one partially and crammed into it (mine is a wide model) and I covered us up with the other bag. We shivered together for twenty minutes or so, behind those little bushes, and unbelievably, we warmed up in that wet bag. With the temperatures dropping and the wind whipping the prospects were ugly. I was really amazed how that bag was holding in our heat, what little we could generate, even though it was totally soaked and was sitting on wet, boggy ground.
I had an Iridium Satellite Phone with me, but it had gotten wet and wasn’t working. I had it in a watertight bag, but during the impact something had ripped a tear into it. I laid it out on a clump of grass to dry, praying it might work later after the wind had blown on it for a while. Knowing we needed something warm inside of us, I left my son in the bag and threw on some rain gear I had salvaged, and then ran around the shore and picked up some more stuff that had washed ashore. I hung what clothing I could find on the bushes, so that it could begin to dry in the wind as well. The gear I found included the dry bag with my small stove, along with a metal bowl, and some of our food bags. I started shaking again—as the sun was going down and getting low in the horizon the temperature went into the forties, and with the wind chill it was just unbelievably cold. I started shaking again too bad to continue gathering stuff, so I went back to my Wiggy’s bag and got inside. This time I just grabbed my son’s bag (he was still in mine) and jumped inside. I warmed up in minutes---it was the only “shelter” we had and it felt so good it's hard to describe. I stayed in the sleeping bag this time. I had found two of our foam pads during my search and put one under my son and the other under me, which got us out of the bog at least and made an improvement in the situation. What was strange was the sleeping bags were drying in the wind, even as we were inside them. The moisture was wicking out of them, and they seemed to get better and better and warmer at the same time. From the sleeping bag I lit off the stove, boiled some lake water, and made us two cups of hot cocoa. It tasted so good! After drinking it I was thinking more clearly, and remembered I had a spare battery for the Sat phone in my survival vest. I got it out and put it in the phone and this time it worked.
I made the call I needed to make, and luckily, I had passed the GPS coordinates of our campsite to my wife the night before. She still had them. After that, we just huddled in the sleeping bags and stayed warm, in spite of the dropping temperatures and high winds. I figured with less than an hour left of daylight we would probably have to spend the night, but luckily, an Alaskan State trooper flew out to us before the sun went down. With some red pen gun flares I had in my vest and the GPS coordinates he was able to locate us without any searching. The subsequent ride out of there in his floatplane was the best flight I’ve ever had. That night the temperatures plummeted into the 20's.
Wiggy, thanks! Plain and simple, you make an incredible sleeping bag. It works, and does what you say it does, and more. For me, and for my son, we are alive today because your product insulates, even when wet. If I had brought my down bag instead, I would never have made it. So, I thank you personally, and appreciate your sleeping bags in a way few others will ever know. Every single one of your employees should take pride in the work they do, and the efforts they make. All of you have my gratitude.
With my sincerest thanks,
John C. Dieffenderfe