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Ask Me: How Can You Tell How Warm a Down Jacket Is?

In Ask Me, Backpacking, Gear Reviews, Hiking, Paddling, Skiing   |   Tagged , , , , , , , , , ,   |   2 Comments


With sleeping bags, we have temperature ratings. But with down/insulated/puffy jackets, what is best way to determine if a jacket will be warm or warmer or hot? Is it the amount of fill? Some but not all jackets indicate the amount of fill.



P.S. heading for Overland Track.


Hi Bruce,

You’re right, puffy jackets don’t have ratings like sleeping bags (which, by the way, were not uniform for many years, though there is now a uniform bag-rating system).

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2 Responses to Ask Me: How Can You Tell How Warm a Down Jacket Is?

  1. Jeffery Koski   |  October 28, 2017 at 4:37 am

    How can I, if possible, estimate the comfort zone of a down sleeping quilt that’s been modified with more down?

    I bought a 850 FP grey goose down quilt to replace my down sleeping bag. This quilt is rated for 5°C. I then took a small goose down comforter and had the fill removed and placed in the quilt. I haven’t yet slept using the quilt outside as the temps here are still in the upper 30s to 40s.

    Is there a way to estimate its warmth value now that more down was added?

    • MichaelALanza   |  October 28, 2017 at 6:43 am

      Hi Jeffery,

      That’s a good question. The temperature rating of sleeping bags and quilts is set using a standardized method; see my “Pro Tips For Buying Sleeping Bags” ( for more explanation about that. Estimating a temperature rating without using that method would be like estimating the width of a doorway without using a measuring tape; you’re likely to be off by a bit.

      But the quilt’s warmth will depend on how much down you added to it, of course. You’d measure the weight of the down added and compare it against the amount of down the quilt had prior to modifying it (which is often available in manufacturer descriptions of a product online). You could also have measured the quilt’s total weight prior to and after modifying it, and subtract the weight of the quilt’s fabric from those numbers (calculate the fabric’s weight by subtracting the weight of the down in the original quilt from the quilt’s original total weight). Did you increase the amount of down by a fairly small fraction, or by as much as 50 percent, or by some other value? That would begin to give you an idea of how much warmth you added.

      A quilt’s warmth is also affected by its design, and the fact that it doesn’t seal up as completely as a sleeping bag. There’s a limit to its ability to trap body heat.

      My advice: If you had not used the quilt before modifying it, don’t make any assumptions about how warm it’ll be now; just experiment with it in temps around its original rating or slightly lower than its original rating. Have some warm clothes to wear to supplement the quilt when you start experimenting in temperatures that may test the limits of the quilt. How warmly you naturally sleep is another variable that can’t really be calculated.

      I hope that’s helpful. Good luck.

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