How good is it?

19 messages
12/11/2008 at 09:50
There have been a few threads on OM recently about synthetic mid layer and belay jackets, and they got me thinking about how good the most often mentioned type of insulation, Primaloft, really is. It's claimed to be the next best thing to down, but in my experience it isn't even in the same league. I've got a Primaloft jacket (although it's not one of the heavier belay-type ones) and vest, and while they're pretty warm, I wouldn't describe either as toasty. In fact they seem very thin and, when a strong wind "plasters" them against my body, they don't feel as if they've got any loft at all.
By contrast, an old jacket I have with a fill of Polarguard or something like that does give that impression of almost instant warmth. I'm not saying it's as warm as down — and it weighs a fair bit and packs down to the size of a Triumph Herald — but it does feel like a winter garment.
So, am I expecting too much from Primaloft insulation? Does it perhaps perform better in the laboratory than on the hill? Have I been unlucky with the garments I've bought? Or does it just lack the psychologically warming "fortress" factor?

12/11/2008 at 10:14

Sounds like your Primaloft stuff is thin like mine

The same thickness of Primaloft isn't as warm or as light as good quality down, and I agree that once a strong wind plasters a thin Primaloft garment against you, it loses warmth too, even under a windproof.

Still find Primaloft better than a fleece (warmer, lighter, compressible etc) and complementary to down as it keeps working when wet ...

My thin Primaloft jacket gets used when moving or on cool evenings, reserving a 10cm thick down jacket for sitting around or Winter.

12/11/2008 at 10:57

Guy, it really is the next best thing to down, AFAICT.  But that doesn't mean it's anywhere near as good, just that your other alternatives are even further away.

I think the bad luck with garments for you is that you're looking for a real toaster in a market which emphasises low bulk and light weight more than outright toasting.  Fact is, if it's that cold you need a really warm jacket then down is probably the better option, because it's cold enough not to be wet.  Bit of a shame if you're allergic to down, of course...

With down so much better at much lower temperatures the typical Prmaloft jacket has a fairly small niche to fill: those times when it's colder than a fleece will do (fleece needs less care as it doesn't suffer from compression and is more immediately comfortable due to its furry texture, and it's much, much cheaper), but not as cold as a downie where you'll worry about the down getting wet.


12/11/2008 at 12:26


 What you need to remember that Primaloft like any other filling has varieties and certain properties.

 "Primaloft" is simply the brand - within that there are several different types of wadding - One and Sport being the most well known and then within those categories that are a multitude of different weights (or thicknesses). Ultimately what weight you use has a fairly big impact on how warm the product will be. Even if you had 99% Pure Down of the highest quality, put only a few grams of it in a jacket and you will get cold, no matter how good it is!

Now Primaloft is very light, it can also have exceptionally good hydrophobic qualities (with One) and it is very compressible with low loft. This latter point is what makes it such an obvious choice for clothing - where excessive loft or bulk will inevitably restrict movement. Hence why you see versions of it being used by so many outdoor companies.

However that does not mean that Primaloft is the best synthetic fill for everything. There are others, you mention Polarguard, which are very good in certain circumstances. Polarguard having more loft, in our experience better compression resiliance thus making it ideal for high-end synthetic sleeping bags.

Do any compare with down? Well, I guess by that you have to look at the instrinsic qualities that most people look for with down - a given level of warmth for the least bulk and overall weight. In that sense Primaloft scores very highly.

Richard Talbot - Product Manager - Mountain Equipment

12/11/2008 at 13:12
Quite a useful discussion here.
12/11/2008 at 13:23

Interesting stuff, as I have found the same with my 3 yr old 60gm Primaloft garment.  Treated very carefully, never squidged up into small space but it does not have much depth or thickness to it now - much less so than a mate's new one.  It's not been worn that much.   And yes, under rucsac straps or with wind pressing against me, it does not feel that warm.  But I like it for low bulk warmth for stops, but less so for wearing on the hill because unless it's very cold, I tend to sweat in it - or at least used to, before I realised it was less versatile than a thin fleece and windshirt.  It is also useful as a back-up to a waterproof - the jacket is very water resistant so it's good to have in case someone in the party has a duff jacket.

So, in short, I'm not convinced with the current 'thinking' that fleece is naff and synthetic fill is the way to go.  And fleece lasts forever!

12/11/2008 at 13:32

Richard Nisley posted the following technical information in the BPL US forum earlier this year:

"As an UL backpacker, I assume that the primary clo metric you are interested in is clo/oz:

-The now discontinued Polarguard Delta is .68 clo/oz.
-Standard down (550 fill power) is .70 clo/oz.
-Cimashield XP is .82 clo/oz.
-Current Primaloft One is .84 clo/oz
-Primaloft One Convexion is .92 clo/oz but, it will not be generally available until late summer or early fall.
-800+ fill power down is 1.68 clo/oz at the density used in most UL manufactures products such as Mont-bell's (2.16 kg/m^3)."

Clo/oz is a generally accepted abbreviation for clo/ounces per square yard.  The manufacturer will quote a clo/oz figure for a particular thickness of a material.  If you then use two layers you double both the weight and the clo, or insulation value.    

12/11/2008 at 13:37
 Learning again.
12/11/2008 at 13:48
Interesting letter there Captain, especially the bit about Primaloft's apparent lack of durability. Both my jacket and vest are a few years old and have had a fair amount of use, although I wouldn't say maybe 20-30 days of wear for three years is excessive, and they've not been stored compressed. It might be that they have lost a lot of insulating property, and if so it's very disappointing. I was aware that synthetic fills are not as resilient as down, but it's a bit hard on the consumer if some are as poor as that (and it's certainly not something the manufacturers have chosen to tell consumers about).
Thanks for your input Richard. When I come to think about it I reckon the old jacket I mentioned was a Mountain Equipment model — perhaps the Maestro. Don't suppose you do, or plan to do, a similar jacket with an insulated hood?
12/11/2008 at 18:18

Hi Rob

'my 3 yr old 60gm Primaloft garment ... does not have much depth or thickness to it now ... under rucsac straps or with wind pressing against me, it does not feel that warm ... unless it's very cold, I tend to sweat in it'

Mine (an Integral Designs PLQ) has seen perhaps 90 days partial use, and has been squished in my sack about 240 days. Its loft (and smell ) has been slightly improved by a light wash and tumble dry, although check your care label first ...

Cheers Judy

13/11/2008 at 13:34

Hi Judy,

Thanks - I'll try it.  I did wash it carefully with soap flakes a while ago but don't have a tumble drier.  I'll ask a mate if I can use his!

Primaloft is funny stuff - I love it in some ways, distrust it in others.  Mine seems terribly thin now although used really very little.  Under a wateproof, I can't see how it'll be very warm, when its windproof qualities are usurped by the outer jacket.

13/11/2008 at 14:19

I think PL's compressability might be a potential weakness. I still like the stuff and have a couple of items for different uses - a 60gsm lightweight gilet and a heavier (probably 130gsm) belay jacket. Both are doing fine at the intended job. But being more compressible than a classic fleece, it suffers more when under pack straps or in strong winds that squish the air out of the insulation.

I've not really found this to be a problem as yet, but I can see how it could be. And that's before you consider the degradation of performance over time. I think you are right, Rob, that much of PL's claimed insulation over a fleece is derived from being intrinsically windproof once sandwiched between two layers of pertex or whatever. I still opt for a microfleece & windshell over the lightweight PL for most active uses. The PL gilet is, however, an easy way to carry a bit of extra warmth when I (or my other half) needs it... and being smaller than a fleece once compressed, it is more likely to get carried.

Here's my review.

13/11/2008 at 14:36

I guess that if compression is really annoying someone then there's always Buffalo's belay jackets and friends. Of course they're a little heavier for the warmth and much bulkier in the pack - comes of not compressing

So not great for camping trips but might be workable for day walks and for allowing primalofts stuff lifespan to be extended by only carrying it when weight/bulk really matters.

13/11/2008 at 14:45

Indeed, Martin, that's exactly what I do. But then I have a burgeoning kit wardrobe so no one item gets used that frequently. I have a few different windshells of varying sizes to accomodate just baselayer to microfleece through to plump thermal pro furry stuff. I also have a Rab Berber Tech Smock for colder weather. Mix and match to suit the conditions and keep the PL stuff for backup & when I need to keep the packsize or weight to a minimum.

13/11/2008 at 18:17
JB and MC - I agree with your approach, and this is how I've come to use my PL jacket - for 'best', when weight and compressability are important.  So it joined a 100 weight fleece on my last trips to Iceland, Norway etc, where it was used for rest stops and in the evenings, quite comfortable under a light down jacket.  The small size is great.  But I prefer fleece in many ways - bombproof and it makes a nice pillow!
14/11/2008 at 11:00

The (slightly scary) Mr Nisley again on synthetics vs fleece:

"Merino wool or two versions of fleece are designed for next-to-skin wear in cool to cold temperatures; those are the Power Dry (.080" loft) and Power Stretch (.130" loft) materials. Either, in a hoody design, will provide excellent variable temperature regulation while backpacking and not be damaged by the pack straps.

Polartec 100 (~.148" loft) Polartec 200 (~.195" loft) and 300 (~.250" loft) are engineered to be mid-layer insulation pieces. As others have mentioned, high loft synthetics (typically .400” - .600”) are lighter and compress smaller for any given temperature rating.

The key thing to remember is that you generate, on average, about 7 times the heat when backpacking as when you are taking a rest break. For times when you are active, you need only a relatively thin base layer and a wind shirt to maintain body warmth. Fleece variants such as Power Dry and Power Stretch have a thickness optimized for this function. Also the bi-component structure efficiently wicks moisture. When you are inactive, you need about 7x more insulation for the same temp. This is the scenario in which the benefits of high loft synthetics generally win out over conventional fleece (Polartec 100, 200, and 300). This is because at this level of loft requirement and above, high loft synthetics weigh less and compress smaller.

As an example, let’s assume that you are climbing over a mountain pass in a storm. A .080’ Power Dry or Merino wool, in combination with a wind shirt is keeping you warm. Now let’s assume you sit down and rest for an hour. You will need about 7 times the loft to now maintain your warmth. Let’s assume you are carrying a Patagonia pullover (.600” loft). You put it on and again are comfortable. You would need to carry a Polartec 300 jacket and Polartec 300 vest to approach the same warmth as your Patagonia pullover. The weight and pack volume would be dramatically heavier using the fleece option when inactive."

14/11/2008 at 20:15

Scary yes but interesting and fun

Insulated tops do of course also require two layers to hold in the insulation, so - with zips etc - you've got 150-200g non insulating weight. Not so good for a 200g mid layer....

Interesting how pertex/pile compares - it only needs one outer layer too of course which does save a little weight. A little bit more efficient than fleece too.

There was a synthetic sleeping bag review back in TGO in July '07 in which CT measured a Buffalo lightweight outer bag as giving 2.5cm of loft at 861g - the same as a 50g/m2 fill bag from Vaude (which was only 671g.).

So the loft/weight comparison isn't too bad at low fill weights. The extra ability to deal with moisture gives it a comparative boost as external insulation. Bulk still a huge issue of course.

There is a slight issue that there's only one vaguely light  p/pile insulation piece (the Bufalo reversible gillet). Buffalo's other ones are full on belay jackets so don't compare to generators and the like.

Actually, looking at the threads around about buying fabrics/making stuff, it would probably be a reasonable project to get some fibre pile and make a really basic thing with a superlight outer windproof fabric on it. Total fabric weight ~350g/m2 so what 450g overall in a pullover?

Maybe a gillet would be better for day walk insulation. Should be a bit easier to make than a insulation filled stuff. Very much liable to remain an idea this of course

Only useful for mostly carried external insulation this I should add - for actual wearing the features and heavier face fabrics on the main smocks are well worth it. Even for a second layer you're expecting to wear really.

18/11/2008 at 16:44


indeed, I think that its difficult to compare down to primaloft, mostely because the range of primaloft jackets is always light.

I wonder, does anyone have an idea which jacket is the most thicker from the synthetic primaloft insulation pieces?

18/11/2008 at 18:07

There is of course two primaloft types: - Primaloft 1 and Primaloft sport. The first is generally the premium version. Also, you have different fill weights like down so if you are coldblooded go for a heavier weight just like you would for down or even fleece.

Down is supposed to have a longer life, by that it keeps more of its insulating properties for longer than synthetics even primaloft.

All insulation relies on loft. Straps and strong wind like you guys mention will effect the insulation. I guess empirically you are finding that primaloft does not hold the loft as well as down or the older synthetics such as polarguard delta. It's all a game of compromise and no one solution is right.

So you know what that means....

Get one of everything. More gear shopping.

So who else wants to get a primaloft jacket, downjacket, fluffy double pile / berber style fleece and pertex pile smock so all eventualities are covered.

I reckon primaloft is still a very good solution to the coldish and moist weather we get in the UK. Down is better for the colder climes such as Nepal, Alps, artic / antartic, etc. Just don't expect longevity.

Your say
email image
19 messages
Forum Jump