Down-Filled Backpacking Quilts (Market Survey and Gear Guide)

And one other comment too, I have read before that 900 fill power (usa) is equivalent to about 850 fill power (eu).
Is that true or do they all use the same test method and unit nowadays?

@ Jeff

Mating an EE to a ZB sheet isn’t too difficult, but keep in mind that the ZB sheet will bunch up and twist a bit on your pad as you sleep at night and roll side-to-side. I’m a rotisserie side-sleeper, too, and its the reason I ditched my ZB sheet. I tried the same with a ThermaRest Synergy sheet with the same results. If you figure out how to get it to work, please let us know!

My solution for my Katabatics is to affix snaps directly onto my pad and then use 3/16 shock cord and mini barrel locks, mated to a snap on a grosgrain loop, to hold the quilt in place. Like you, I’m a bigger dude and my quilts are all wide widths and this works fine for me. I don’t sleep in the buff, so that helps a bit, too. I have slept in this system down to 30° with no issues.

And one other comment too, I have read before that 900 fill power (usa) is equivalent to about 850 fill power (eu).
Is that true or do they all use the same test method and unit nowadays?

It’s weird to think that manufacturers in Europe would use that rating since it involves Imperial units (ounces and cubic inches).

https://www.facewest.co.uk/down-fill-power-explained.html

Subtract 50 from Eu measurement to get u.s. measurement.

Yeah, weird that eu uses cubic inches.

Subtract 50 from u.s. measurement.

Subtract? Add?  Whatever…

@JG H Thanks for the tips about the Zenbivy sheet!

I have an OG Enlightened 20degree quilt that’s about 13 years old now, but I had EE add more down fill to it during COVID when they were offering that service.  It’s gonna be 30 degrees overnight this weekend and I’ll be using it.  I don’t have a Zenbivy sheet to experiment with yet, but I have a decent set of pad attachment straps and I plan to overcompensate a bit with a Thermarest NeoAir XTherm mummy.

I estimated a numberof scenarios (silk, nylon, different MYOG fastener methods) to make a zen-bivy sheet like idea before that product ever showed up and there was no combo or material type and weight that seemed better (lighter) than just getting a wider quilt

Adding a data point from a synth-by-necessity user, synth quilts are much lighter and sleep warmer than any “lightweight” synth mummy bag.

After buying and trying a couple best options, I’ve yet to discover a synth bag anywhere near the weight of an equivalent quilt that tolerates side sleeping and rotisserie sleeping without exposing the cold under-stuffed part of the bag and waking me up shivering.  That’s always proven much harder to manage during sleep than quilt drafts with straps.

I concur that the ZB sheet does tend to twist up and honestly, I don’t like being latched in. That’s the reason I went with a quilt. That said, on a cold night, it’s hard to beat the ZB hood.

I may have missed it in the report, but for me an important consideration is packed size. I use a 36L pack and it is difficult to fit everything inside it.

Re: packed size:

Since temp rating will likely be your primary consideration, it follows that packed size will be smallest for quilts that are narrower rather than wider, and made with the lightest fabrics and highest FP down – i.e., quilts that have the higher warmth index at a given fill volume/temp rating.

Look for a manufacturer’s stuff sacks and they’ll often list the recommended size for specific quilts.

I believe the value rating should include packed size. I aware of all of the point made regarding material and manufacturer’s suggestion.

Hi!

Thank you Ryan for the work, measuring all the quilts.

I want  to develop the ideas of Jerry Adams measuring Warmth and the Warmth Index  with the help of the R-Values instead of using the  Fill Volume.  To do this, consider 2 quilts (both with draft collars) which can be  converted into a blanket, which makes the calculations easier.

a) EE Revelation 20 with draft  collars R/R and  950 fp (Target loft 2.5’’): 

Fillvolume (in cuinch) = FillWeight x Fiillpower =  15 oz x  950 =  14’250 cuinch

Surface of the blanket  =  Length x (Shoulder Width + Foot Width)/2 =  78 x ( 54+ 40)/2 = 3’666 inch^2

Height Loft = Fillvolume / Surface = 3.88’’

Overstuff = Height Loft / Target Loft (or better measured loft would be better!)  = 3.88 / 2.5 = 1.55 This estimate gives a rough overstuff of 50 % (EE claims at least 30 %). Not to bad estimate, probably the quilt has a bit higher loft than the target loft.

R-Value (per inch 2.5, overstuff 1.5 per inch if overstuffed 100 %, see comment of Jerry Adams):

R-Value = 2.5 x Target Loft (measured Loft) x (0.5 + 0.5  x Overstuff)  = 2.5 x 2.5 x (0.5 + 0.5×1.55) = 8.0

R-Value per oz =  R-Value / Weight Quilt = 8.0 / 21.7 =  0.37

b) Katabatic Flex 22 with draft  collars R/R and  900 fp (Target loft 2.75’’): 

Fillvolume (in cuinch) = FillWeight x Fiillpower =  14.3 oz x  900 =  12’870 cuinc

Surface of the blanket  =  Length x (Shoulder Width + Foot Width)/2 =  72 x ( 54+ 40)/ = 3’384 inch^2

Height Loft = Fillvolume / Surface = 3.80’’

Overstuff = Height Loft / Target Loft (or better measured loft)  = 3.8 / 2.75 = 1.4. (Better estimate ?)

R-Value (per inch 2.5, overstuff 1.5 per inch if overstuffed 100 %):

R-Value = 2.5 x Target Loft x (0.5 + 0.5  x Overstuff)  = 2.5 x 2.75 x (0.5 + 0.5×1.4) = 8.25

R-Value per oz =  R-Value / Weight Quilt = 7.5 / 22.8 =  0.36

Hopefully the numbers and calculations are correct. Therefore I would claim that both quilts are similar in performance (R-Value and R-Value per oz).But these numbers are numbers, other variables (sleeping behavior, draft control system,  …..)  might be more important.

Thanks for exercising my neurons, you’re helping me to delay dementia :)

That makes sense – you’re overstuffing 55%.  And R value with fully lofted is 2.5 R/in × target loft (2.5 in) = 5 R.

The overstuffed down (0.55) would produce half the R value of fully lofted down (1.0).  So that would be one half of 0.55/1.0 × 5R = 2.75 R so total R = 7.75 R.

Except you rounded the 0.55 to 0.5, so it would be half of 0.5 / 1.0 = 2.5 R = 7.5 R.

Does that make sense?

There must be some more straightforward way to calculate this:)

Regardless, your conclusion is good, the two are similar and other variables that we arent including are important.

Dear Jerry

Thanks for your answer! I think, that your calculations are not quite correct. You use

R-Value =. 2.5 R/inch x MeasuredLoft of Quilt  x (1 + Overfill).

So an overfill of 100% (I.e. Overfill =1.0) would double the R-Value:  The quilt of Target Loft 2.5’’ with 100 % overfitting would be equivalent to a quilt von 5“ with no overfitting.

My equation is (overfilling is half efficient):

R-Value =. 2.5 R/inch x MeasuredLoft of Quilt  x (1 + 0.5 x Overfill). So an overfill of 100% for a quilt of target loft 2.5“  is equivalent to a quilt of 3.75“.

Hope this makes my calculations a bit clearer :-)

You are kind to say ” I think, that your calculations are not quite correct. ” : )

“R-Value =. 2.5 R/inch x MeasuredLoft of Quilt x (1 + 0.5 x Overfill). So an overfill of 100% for a quilt of target loft 2.5“ is equivalent to a quilt of 3.75“”

That is a much more straightforward way to think about it.  That makes sense.  I agree.  Thanks.