UKH

Firstly I am assuming that Primaloft One is now Primaloft Gold, and Primaloft Eco is now Primaloft Silver Eco (i.e. they just changed the names) - I have no real evidence for this though so let me know if I am horribly wrong...

Is there are a big difference between the two fabrics? The only quantitative ratings I can find are comparing Primaloft One, Sport and Eco:
Primaloft One: 0.92 dry / 0.90 wet, clo/oz
Primaloft Sport: 0.79 dry /.72 wet, clo/oz
Primaloft Eco: 0.68 dry/ 0.60 wet, clo/oz
http://coldthistle.blogspot.co.uk/2012/11/primaloft.html

Converting 60 g/m^2 One and Eco into SI R values, you get (dry): 0.30 K m^2 / W and 0.22 K m^2 / W.
Or in ridiculous American units (like for sleeping mats etc): 1.71 hr ft^2 °F / Btu and 1.27 hr ft^2 °F / Btu.

This seems like quite a difference? I have been looking at the range of Montane synthetic jackets and they are (nearly) all [Silver] Eco, whereas Rab seem to have stuck with One(/Gold?). There is currently a women's Flux jacket going for £80-something in a local shop, but I am wondering whether with its (mostly) 100 g/m^2 fill it will be any warmer than say a Rab Xenon X hoodie which is only 60 g/m^2 but the better Primaloft fill. Just looking at the numbers 60 g/m^2 Primaloft One should be 80% as warm as 100 g/m^2 Primaloft Eco (i.e. probably hard to tell the difference), but the Xenon is 390g instead of 620g. Normally I get Montane stuff because it appeals to my slight perfectionism but I am just not really sure why they went a bit cheapskate on fabrics here - or maybe it makes little/no difference in practice? Just curious (and debating whether to grab the jacket if it really does fit!).

In reply to andrewmcleod:

Anyone with an opinion on the difference between cheap/expensive Primaloft in real use?

In reply to andrewmcleod:
For the jackets you are talking about (ie 60-100g fill) what you are really talking about is weight/bulk vs cost. I wouldn't get too bogged down in the numbers, if you can afford Gold then get it. If not, carry a few more grams on your back.

Continuous filament insulations like Primaloft Synergy or Climashield are also worth consideration if durability over CLO values worth more to you.

That being said I bought a Nano Puff equivalent for £19.99 from Mountain Warehouse and I love it. It has been amazingly warm and I don't care if it gets trashed. I find it hard to believe if I bought the Patagonia version I would be sitting in it thinking 'I'm so much warmer'. Then again, if you break the money on their gear you probably have to.

In reply to andrewmcleod:

I think the Primaloft One/Gold feels warmer. Actually, it just feels very warm for the weight and thickness, and how soft it is, if you know what I mean. So surprisingly warm, whereas Polarguard or Sport/Silver just feels as warm as you would expect. That's as far as my comparison gets anyway.

There doesn't seem to be much 'Gold' about for some reason this year. Perhaps they want people to opt for the down mix and make more money by dividing preferences into Gold+Down or Silver.

I find a waterproof outer makes a lot of difference to how warm a hooded jacket feels, so if I was in the market for something this year, I would get the Rab (Inferno?) jacket with the waterproof outer and whatever synthetic filling it comes with. For something more breathable, I would then try the Alpha stuff.

Good quality down with the newest DWR treatments would probably last longer, be lighter, and cost about the same perhaps, as 'Gold' - so why not consider that as well?

Jon

In reply to andrewmcleod:

I have a Primaloft One belay jacket with a waterproof/breathable membrane outer (Hyvent/Alpha) which is phenomenally warm (133g fill) but very comfortable to wear (stood still at a belay or worn over next to nowt on the move), while my Montane Prism Primaloft Eco with only 40g fill feels rather crushed and clammy.

I'm not sure what this tells you but anecdotally the Primaloft One feels much softer and more breathable.

They are both great jackets however, just for different jobs. The Prism is cheap and rough enough to throw on the pub floor and is a summer belay layer/raincoat. The fancy one is for proper winter.

In reply to andrewmcleod:

So it seems like the Gold/One is worth getting if you care about the weight. Will also have a look at treated down as well... thanks all