Down to synthetic comparison chart

[Mouseskowitz]

There have been a lot of questions lately regarding down vs synthetic. I grabbed a chart from somewhere but I'm not sure who the author was, if it was you please let me know so I can credit you. Some people were having a hard time understanding that chart, so I updated it. This should represent the down, Climashield APEX, and Primaloft Gold and Silver available from our favorite DIY suppliers. Please let me know if anything needs to be added, needs clarification, if I mistyped, or if something is just plain wrong.

Edit: the original work was done by Just Bill, I deleted my version as there is a new and improved version here

[Boston]

I question his temp rating/CLO and wonder how that was determined. What does he assume is being worn? This is the biggest factor in making this comparison.

For instance, I've done a similar analysis for warmth using information found on BPL for CLO requirements and down loft requirement's. For 40*F The chart says, for sleeping, ~5.5 total CLO is needed. If I assume 2 CLO of clothing worn (which I believe is similar to underwear, hiking shirt, mid-weight wool base layer, socks, and hat) then you need 3.5 CLO from your sleep system. This is based on a metabolic rate of 0.8 MET.

By this chart it claims only 2.5 CLO is needed. That's a significant difference.

[genixia]

I think that might be Just Bill's chart from bpl.

[Mouseskowitz]

I think that might be Just Bill's chart from bpl.

You might be right. I'm waiting to hear back from him.

[BillyBob58]

Very interesting chart, if correct. But, the loft for down, at a given CLO, does not correspond to the loft for CS XP or Apex. For example, look at the CLO of 2. This does correspond to my experience with a temp rating of 40-50F. (In my test wearing cotton T shirt and jeans and a fleece hat) However, there is a loft listed of 1.5" for down with CLO of 2. CS Apex with a CLO rating of 2 ( which weighs 2.5 oz sq yd) has a loft of only 0.6". Less than half that of down for the same temp rating.

The other thing I notice here is- again if this chart is correct- that there is no significant weight advantage for 800FP or less down vs CS Apex. Notice the weight for 800 down with a CLO of 2 = 2.43 oz.sq.yd vs CS's 2.5. That is mighty close.

[SirMarkos]

There have been a lot of questions lately regarding down vs synthetic. I grabbed a chart from somewhere but I'm not sure who the author was, if it was you please let me know so I can credit you. Some people were having a hard time understanding that chart, so I updated it. This should represent the down, Climashield APEX, and Primaloft Gold and Silver available from our favorite DIY suppliers. Please let me know if anything needs to be added, needs clarification, if I mistyped, or if something is just plain wrong.

Great job updating the chart! Thanks for the work!

I question his temp rating/CLO and wonder how that was determined. What does he assume is being worn? This is the biggest factor in making this comparison.

For instance, I've done a similar analysis for warmth using information found on BPL for CLO requirements and down loft requirement's. For 40*F The chart says, for sleeping, ~5.5 total CLO is needed. If I assume 2 CLO of clothing worn (which I believe is similar to underwear, hiking shirt, mid-weight wool base layer, socks, and hat) then you need 3.5 CLO from your sleep system. This is based on a metabolic rate of 0.8 MET.

By this chart it claims only 2.5 CLO is needed. That's a significant difference.

I think you're right. But what this chart does provide is an excellent baseline, or starting point, for folks interested in what they can afford, expected bulk, weight carried, and a general comfort rating.

Us data nerds can mull over the specifics but the reality is, there are far too many variables to consider for any chart to fully express real world use and comfort levels of all individuals.

[Mouseskowitz]

Very interesting chart, if correct. But, the loft for down, at a given CLO, does not correspond to the loft for CS XP or Apex. For example, look at the CLO of 2. This does correspond to my experience with a temp rating of 40-50F. (In my test wearing cotton T shirt and jeans and a fleece hat) However, there is a loft listed of 1.5" for down with CLO of 2. CS Apex with a CLO rating of 2 ( which weighs 2.5 oz sq yd) has a loft of only 0.6". Less than half that of down for the same temp rating.

I might try to add something to note the thickness of the synthetic insulation.

[Mouseskowitz]

Here is the new thread with the new version that Just Bill made of the chart.