Question on synthetic insulation

It means they weight in grams per Square Metre of fabric.

So, in theory, a garment could have a higher value for weight square meter of fabric yet still not be warmer, all things being equal, correct?

Yes, it depends on the CLO of the material. You should look up Richard Nisleys posts.

Will do that, thanks Stephen. On a side note, I am seriously picking up a Mountain Equipment K7 jacket at some point. What do you think of the K7?

Just by taking a peek at the stats, with 11.5 ounces of down fill, box wall construction, 27.5 ounces overall, that looks like a seriously warm jacket for very cold weather. If you share what your intended uses are then you will get a better recommendation from everyone.

Hi Paul, Mostly going to be wearing it in the Alps or equally dry/cold mountain tops when I'm doing non-technical alpine trekking. I've already got some Absolute Zero Parkas, the Mountain Equipment Annapurna jacket but was thinking of adding the K7 to the mix at some point. Just wasn't sure what people's general thoughts were on that specific jacket. Eric

Yes, it is the measure of the insulation in grams per square meter. I use the value as my my first thumbnail evaluation of a garment: I know that 60g is the stuff used in thin jackets like the Patagoinia Nano Puff. I like 100g fill as it provides some real loft and warmth. From there I would go to down as thicker synthetics would get too bulky and heavy for good efficiency. 200g insulation implies colder dry weather where down excels. A 200g fill garment would make a better work coat than a backpacking item. Synthetics are great for cold wet weather, say 25f-50f where you are dealing with rain, high cold humidty or melting snow. If it is colder than that, it isnt raining and the humidity is low and down is great. You normally wouldn't be actively hiking with any of this stuff on: it is used for rest stops and camp. I use base layer and wind/rain shell when hiking with a load. I pick my base layer for the general temperature and add gloves and hat as needed. When I stop, the puffy stuff comes out and is added to the mix. I like breathable, wicking fleecy mid layers for cool wet weather. R1/Dry Power and High Loft grid fleece are great for living in the clouds.

The K7 looks nice Erik, as you know I have the Gasherbrum which Is the next parka up.

Thanks Dale! My plan of attack goes like this. I'd wear over my baselayer either a Patagonia R1 or some equivalent followed by something with Polartech Alpha and finally a shell (at the most). If the weather were to go really sideways, I'd opt for pulling out a 100 or 200g Primaloft Gold filled item or if its simply really cold, I would put on either a lightweight down (or heavyweight like my MHW Nilas). These items, down or synthetic, would certainly not be worn while on the move. And then my heavy down parka would be worn around my destination, which for me would be an alpine hut or other such similar location. Thanks for the info! Eric

Hi Stephen, Yeah, I think the K7 would be better suited for me as I'd be willing to sacrifice something in the weight for a more durable exterior fabric. I know Gore used to have their DryLoft (which is on my circa 1995 TNF heavy down jacket) but doesn't appear to be used by anybody anymore. What happened to Gore DryLoft?

Look for Windstopper as Dryloft was actually never nothing more then Winstopper for insulation.

Hi again Dale, So here's where it gets confusing when the numerical value represents the weight of the synthetic insulation per square meter: Primaloft® GOLD insulation (100g body, 60g arms & hood) From this, you would think they are saying they use 100g of Gold throughout the body of the garment where as in the arms and hood, they have a combined total of 60g. I've heard some people online refer to this specific jacket (the Mountain Equipment Fitzroy which I've purchased to complement my two Mountain Equipment Citadel jackets) as having a told of 160g of Gold insulation. Manufactures and retailers seems to be using it differently at times, or so it appears to me.

WindStopper for insulation? Wow, they did a good marketing job! Thanks for that insight.

The name they use now is 'Windstopper Insulated Shell'.