I am in the process of building a ul synthetic quilt and I have heard varying reports on how warm 5 oz Climashield Apex is. Does anyone have experience with this kind of insulation?

Vincent,

This is copied and pasted from Tim Marshall's website.

Temperature options:

2.5oz Climashield APEX good to approximately 45*F
5oz Climashield APEX good to approximately 25*F
7.5oz Climashield APEX good to approximately 15*F

Notice the word approximately in each rating. YMMV

What are you using for the outer covering? Do you sleep warm or cold?

Hope this helps. BTW Tim does help us MYOG types by answering questions. He is a good guy. He helped me a lot.

Party On,

Newton

Thanks for the info. I am a somewhat warm sleeper and I will be using a tarp. If the 5 oz Apex gets me in down to 25 I will be happy and somewhat surprised because it only has 1.2 of loft as listed by thru-hiker.

According to thru-hiker, 5 ounce Apex is 1.2 inches, 4.1 clo

According to Richard's chart, 4.1 clo is good down to 52 F

According to Ray Jardine's formula, 1.2 inches is good down to 52 F

Wow, Richard and Ray agree on that one

I don't know why that's so far off Tim's estimate, because Tim is a reliable source of information

Maybe my math is wrong, someone correct me : )

You need 2 layers of 5 ounce Apex for 25 F

Or, one layer of Apex and wear a jacket or vest out of 5 ounce Apex

Hmmm... I wonder because as you said Ray's formula for 1.2" of loft comes in at 52 degrees but if you doubled the thickness you would have 2.4" of loft and that would come in at 4 degrees. Is it possible that Apex somehow doesn't work with this formula?

Richard and Ray are one sided loft - 1.2 inches for 5 ounce Apex

My interpretation of Richard/Ray is 52 F

Tim Marshall 25 F

These are inconsistent

Apex can not be different without defying the laws of thermodynamics : )

I will be interested to see if anyone can resolve this inconsistency

Richard's chart is at http://www.backpackinglight.com/cgi-bin/backpackinglight/xdpy/forum_thread/9378/index.html

My -20 degree down bag has 4 1/2" of loft on Ray's formula that comes in at -80 degrees even though I have used this bag many times and find that it's -20 rating is quite accurate. Also as far as I know there is no bag on the market that is rated to -80. Is it possible that the formula is not accurate?

Is your 4.5 inch loft the thickness of the top layer? or top and bottom layer together?

just the top layer. The top and bottom layer combined would be 7.5" of loft.

I agree, 4.5 inch is -80 F using the formula

I don't know, maybe someone else has an opinion

What brand and model is your sleeping bag?

I was just looking at Nunatak Aplinist sleeping bag, randomly selected - 2.5 inches of loft, they say it's 20 F. The formula would say 0 F. Nunanatak is conservative, that's good. Aproximately consistent.

I have a sleeping bag that's 0.5 inch, I wear a vest that's 0.625 inch, plus a shirt and jacket that are maybe 0.25 inch, 1.375 inch total, 45 F according to the Ray formula, below about 40 F I start getting cold, so that's pretty consistent.

My bag is an EMS Mntn Light -20. I am completely baffled as far as the formula goes. I guess I will just have to make the quilt and hope it keeps me warm to 35 or so degrees. I will post again when I find out the real warmth of 5oz Climashield Apex.

I just googled it - they don't list loft in their specs, looks like a high quality bag with 800 fill (European) down

I bet someone else, like Tim, will say something

Richard and Rays loft information from 2007 is from older generation of climashield verse climashield apex . It seem both climashield and primaloft have been able to manufacture more thermal efficient insulation in lighter weights and thickness of older generations of their products.
Terry

Edited by socal-nomad on 04/17/2011 10:54:27 MDT.

Ray makes a statement in his book Trail Life that two inches of shredded newspaper would have roughly the same warmth as two inches of down or two inches of synthetic (pg 80). If this is true then his formula should accurately measure the warmth of a bag (give or take the persons personal preference). Since it seems like his formula is not working then maybe this is not true and certain insulations can be thinner but have a better ability to trap air or something. Any thoughts on this?

> certain insulations can be thinner but have a better ability to trap air or something

That is true in the home market at least. Standard fiberglass R-19 is 6.25" thick, but you can get "high density" R-21 that is only 5.5" thick.

R-21 = 3.8 R/inch = 4.3 clo/inch

R-19 = 3.0 R/inch = 3.5 clo/inch = 21% less

Styrofoam = 3.9 R/inch = 4.4 clo/inch

taking thru-hikers data Apex is 4.1 clo / 1.2 inch = 3.4 clo/inch

there all within about 25%

Ray's formula isn't so great. 100-40(loft)=temp has never been very accurate for me. His formula says a bag with 2.25" will keep the user warm to 10*F. I don't think so. I have based my down ratings on an old BPL chart relating loft to warmth. It is older and tries to state that warmth is the same for all insulation of a given loft (which isn't true) but has been pretty accurate on down temps for me and i haven't heard any complaints from customers. The climashield is tougher. I have rated it based on real world personal experience along with ratings from customers and tried to balance that against the MLD and thru-hiker(took their ratings down a year ago i think) ratings. I have used 2.5oz down to 30* and it was cold, at about 60* it was too hot, at 45* it was just right (3 bears style) This is similar to others ratings and feedback and so it is where i landed.

It is important to note that each person generates heat differently and the ability of the bag to keep you warm (trap that heat) can be limited by how much heat you generate. I push a lot of heat so a given bag will keep me warm in lower temps then someone who pushes less heat. (yeah i am sure there is no science to support me on this but i have seen it over and over) Also what one person finds a comfortable sleeping temp another person may find cold. These variables make it very hard to offer definitive information about temp ability of an insulation.

-Tim

Take a look at
this page from MLD's website.

It contains the info below that I copied and pasted into this post.

Spirit Quilts

30 Degree
4.8oz sq/yd Climashield Apex (Approx 120gms sq/m)
Small: 15oz
Regular: 18oz
Large: 22oz
X Large: 26oz


45 Degree
2.4oz sq/yd Climashield Apex (Approx 60gms sq/m)
Small: 11 oz
Regular: 13oz
Large: 16oz
X Large: 19oz

Shell Fabric AND Lining Fabric: Momentum M90 20d X 20D DWR
Insulation: 2011 Climashield Apex

These numbers seem to agree with the numbers on Tim's website for the Prodigy quilt. Only the temp rating for the 5 oz Apex is different and then only by 5 degrees, a 25 degree rating vs a 30 degree rating.

Click on the embedded link above and then scroll down to the bold heading Temp Range. Read everything enclosed in the green outline from that point down to the bottom. It contains quilt sleeping strategies and some ideas of what to wear at certain temperatures in either of MLD's quilts.

BTW I'm not sure if it was intended but the Spirit Quilt 30 sleep strategy for a temperature of 35 degrees gave me cause to smile. ;-)

Party On,

Newton

I know this is confusing and trying to come up with definitive conclusions is probably hopeless, but

WM and Nunatak have 2.5 inch loft for 20 degree rating, FF has 3 inch for 10 degrees which is consistent, and Nunatak has 0.75 inch for 35 degree bag

2.5 oz Apex = 0.6 inch = 45 degrees

5 oz Apex = 1.2 inch = 30 degrees

based on those, it's 25 degrees F per inch of loft (15 degrees / 0.6 inch)

then 2 layers of 5 oz Apex would be 2.4 inches and 0 degree F

But the down bags are rated at 20 degree F for that loft

Does Apex have more unsulation value per inch of loft (clo/inch) than down?

If you plot the down bags, plus a 35 degree Nunatak bag, plus the two apex, plus Ray and Richard's formula you get:



I just drew a straight line through the down bags and Apex and called it "hypothetical"

Maybe that's a better formula

49 - 12.3 * loft in inches

Or, maybe I should just be happy with Apex 5.0 oz = 30 degrees, 2.5 = 45 degrees, and call it good : )