ALPHA DIRECT IS NOT AN OUTER LAYER!
Polartec Alpha was designed as a batting insulation, meant to be sewn between an inner and outer shell. The Alpha insulation provided loft and dead air space. The shells provided the structure and capped the air movement. Polartec Alpha Direct was later designed, again as batting insulation, but this time to be sewn to an outer shell. The Alpha Direct provides the inner surface along with the loft and dead air space while the outer shell provides the structure and caps the air movement. Since AD is designed this way, it has it’s own structure and against the skin durability. This led to the cottage industry building stand alone garments out of it, which is a good thing because it can now be used as part of a modular system. AD has one of the the highest warmth for the weight ratios when compared to other fleece products when capped with a shell. Without a shell it has almost no insulation value at all (unless the air is perfectly still and the user is perfectly still). This means that the wearer can pick a shell appropriate for the conditions, and then ventilate it accordingly. Since it has so little insulation when directly exposed, this eliminates the need for a second set of zippers on the inner layer. As long as the outer shell has adequate ventilation and/or breathability there is none needed on the inside, which further reduces overall weight. We can go from having a very respectable amount of active insulation with a shell fully closed up over an AD insulation layer, to being able to completely dump a ton of heat out when the shell is opened up to vent. This covers a really wide range of conditions when you consider that you can mix and match the outer shell to provide rain protection, wind protection, and/or different levels of breathability. If you are in pouring rain you can cap it with an impermeable rain layer but still be able to ventilate it. If you are in high winds you can cap it with a 40cfm wind layer to stay warm but breathe just enough. If you are going for a run, you can cap it with a sun hoodie or something with high breathability so you can dump heat and moisture while working hard.
Alpha Direct is really an impressive product. However, it is not a do-all wonder fabric. It has limitations and hype will often take products beyond their usable range. One thing it does very poorly is function on it’s own, as an outer layer. First, it does not have enough durability to hold up this way. It’s ok to use it this way on occasion when you need to dump all your heat, but the mesh backing that holds the fibers will easily snag on things and break/rip. It rips VERY easily like this so the wearer needs to be very careful. Second, as mentioned previously, AD has almost no insulation by itself unless the air is perfectly still and the user is perfectly still. This is not a realistic scenario for an active layer. The tufts of fiber and the spaces between are the reason that it can be so warm for so little weight when capped, but it needs that cap to hold the air in those pockets. If there is no cap, then those open spaces radiate heat away, even in no wind. A wind of 1mph will cut right through and chill you to the bone. This is not to say you should never use Alpha bare, with no shell over it. This is part of its wide range of functionality, but usually does this particular job worse than other options. Bare AD has about the same insulation as a sun hoodie if there is any air movement, but the sun hoodie will be much more durable against snags and abrasion. The beauty of AD is that this functionality is only one small part of its whole range and you can strip down to this once in a while when you need to cool down while active…but it would be silly to wear a bare Alpha when you are looking for warmth. Its high warmth to weight cannot be realized until it is capped with a shell. Some seem to have found a niche use as a high exertion running layer, where it dumps all the excess heat and moisture well. I can attest to this use, but again, I think other layers do this job much better. A breathable sun hoodie layer will hold up much better, transfer moisture about as well, and provide a more even comfort. Bare AD will tend to be cold on the windward side, while hot on the protected side. It does have the benefit of feeling cool while in motion, but luke warm when stationary in still air. This works well if you’re transitioning between running where you need to stay cool, and stopping where you want some insulation. However, this only works if you’re on buffed trails where you won’t snag, and there is no backpack abrasion, and the air is still when you stop.
Since AD wasn’t designed this way, it also tends to fit poorly as a stand alone layer. The fabric doesn’t have a lot of structure, as it was designed to be sewn to a shell, which would provide this. So it tends to be sorta lose and baggy and needs a well fitting shell over top to hold it together. In many cases, the solution in the industry has been to aim for a sung fit, but this creates a ton of issues. AD has stretch, but again, it was not designed to be used. If you force the fit to utilize this stretch, then the opposing dimension will cinch up. This is the cause of all the cases of ” Alpha shrinking “. I haven’t really ever seen any cases of the fabric actually shrinking from washing or whatever. It’s always a case of the diamond lattice stretching in the girth and cinching up the length. When it is repeatedly stretched like this, the lattice will tend to stay cinched up, making folks believe it ” shrank “. Well, it did, but not because of fiber contraction or felting. It’s purely fit-based.
This is all why you will see the Timmermade Alpha Direct offerings limited to basic insulation layers. Zippers create redundancy in ventilation (unless someone wants one for convenience reasons) and pockets create redundancy since they would be covered up in almost all scenarios while using an AD garment properly. There is sometimes a use case of wanting an inner pocket to hold items underneath a shell, but this happens to be another thing AD does very poorly. It has a very light and stretchy structure, which will not hold weight well. Even the weight of a phone will stretch and deform it’s structure, not to mention bounce around quite a bit.
It’s really great that innovators in the cottage industry are thinking outside the box and pushing products beyond their original design. Good designs inevitably find other uses. However, if we are going to do this, we need to think about our designs. Alpha Direct is a very unique product that should be thought of and built differently than other products.
Some other things to note……
Most of this applies to AD60 and AD90. AD120 has enough fiber to cover over some of the gaps and pockets in the lattice. It is also more durable due to the lattice coverage. Therefore, it ends up being a bit more of a functional stand alone garment than 60 or 90. It still has very high breathability and hence, limited functionality, but not as bad as 60 and 90. Those two really only provide a small fraction of their insulation in still air without a shell. You can literally see through the lattice and if you see through it, you know those spaces are radiating heat directly out, even if the air is still. AD120 has the same lattice, but the fiber count is high enough and they are long enough that the holes are covered.
Alpha Direct 60 and 90 has incredible variation from roll to roll. Some 60 is more like 90 and some 90 is more like 60. It’s pretty much all over the place. I’m pretty convinced that the sentiment that AD60 is the ” warmest for the weight ” is simply that whoever tested the samples that came to this conclusion were testing a ” heavy ” AD60 and/or a ” light ” AD90. In my estimation, an AD variant that is actually 60gsm, is proportionally less warm than an AD variant that is actually 90gsm. There are all kinds of anecdotes out there that say one thing or another, but I don’t think any of it is reliable, just because of how much variation there is. Basically, I think every roll of AD60 and 90 has it’s own levels and characteristics that don’t necessarily line up with the general product specs.
Fiber loss and microfiber accumulation are big concerns and it is pretty consistent that the lighter the AD variant is, the more fiber it loses. AD120 loses very little. Every roll of AD60 we’ve had loses a TON of fiber. The AD90 rolls that are ” heavy ” will lose very little, similar to 120. The AD90 rolls that are ” light ” lose more, similar to AD60.
Personally, I choose to not use AD60. First, the overall amount of fiber loss is unacceptable to me. Even the heaviest AD60s we’ve used loses a lot. Additionally, low end of the variation range of AD60 is getting into an insulation level that just isn’t that useful for me. The heavier AD60s are ok, but we never know what we’re gonna get. With AD90 the entire range of variation is useful to me. I currently have a light 90 and a heavy 90 in my rotation that I use for different temps…..but a light 60 is basically useless for my purposes. AD120 is pretty consistent in quality, weight, and performance. However, it also has somewhat limited use for me, as its weight starts to overlap with the higher warmth to weight performance of a batting insulation. An 80gsm batting garment can typically achieve a much higher warmth level, at the same weight. There are times where the breathability or fuzzy comfort of AD120 are cause to favor it over the jacket…..but if I were bringing trail insulation, I’d probably favor the warmer jacket and use AD in the weight range where it is the only option.