Christina:

First, you have identified a potential scenario most people often overlook. You are willing to provide “creature comfort” in an adverse situation.

Unfortunately, it becomes much more complicated than that. Synthetic insulation has most definitely come a long way in the last 20 years, or so. That doesn’t mean a sleeping bag that is rated for -20° F is going to keep you warm at that temperature. The comfort experienced by humans in a given environment can be classified as a subjective assessment, because it is possible to find a considerable variation in responses of different people to the same situation. Sleeping bag ratings are really just a general formula and not every manufacturer uses the same scale. How can you be sure you will get good insulation for what is required. A sleeping bag works best by trapping and holding air around your body, with that in mind simply follow the steps below to determine what you’ll need.

- Sleep style—adjust upward or downward by 5 to 15 degrees depending on whether you "sleep warm" or "sleep cold."
- If you're slow to adjust from a cushy room temperature of 68 degrees to life in the cold outdoors, then correct downward usually 10-15 degrees downward.
- Clothing—you will probably be using the sleeping bag in addition to wearing “normal street” wear and perhaps even a winter coat. After all, you won't be in any minimal night wear.
- Dampness—When you are in a confined space, such as a car, you will perspire and breathe out water vapor, which contributes to a damper environment. Adjust the rating 5-15 degrees down for synthetic, or 10-25 degrees for down.
- Inactive versus Active—You will be in a confined area, your amount of movement is restricted and blood will pool lower overtime. Try to not restrict movement by using a confining bag.
- Consider a bag with a draft tube and draft collar to help keep cold out.
- Don’t forget to cover the head. You’ll be surprised to find out how well this helps.
- Wear gloves if fingers will be exposed.
- Remember surrounding car metal cools with the air. I have seen cars iced up inside in Idaho, Montana and Canada. This will contribute to overall comfort. If possible, try to run the heater once an hour. Make sure the exhaust pipe is unblocked though.
- As mentioned, a sleeping bag in long term storage, or even stored incorrectly, will lose insulating value.

How much money you plan on spending is dependent upon what you can afford. You mentioned you wouldn’t be buying a Wiggy’s, but keep this in mind; will the sleeping bag be used for anything else? If so, then consider “exceeding your budget!” You definitely don’t want a series of unsatisfactory purchases. Coleman, The North Face, Slumberjack and Marmot all make good bags. I hope this helps.

Take care,

Stargazer

"Pay no attention to what the critics say... Remember, a statue has never been set up in honor of a critic!"