Hooded vs non-hooded active insulation

[4th_point]

more than once in cold weather with wind i was glad to have a double hoods ... never tried removable hood too fragile in my opinion ...

I've got a hood on my shell for that. And stocking cap, balaclava, buff, or standalone insulated hood as needed depending on season.

Built-in hoods are idiot proof though - can't leave it behind!

 

[Macintosh]

@Pilsner “Active insulation” is a category of materials that supposedly breathes exceptionally well and allows for a wider range of temps so you need to put on/take off less in order to regulate temp. Primaloft evolve, polartech alpha, alpha direct are some of the main fabrics in this category.

 

[Poser]

What is an "active insulation layer"?
I ask this because if I am active I don't need much insulation...

Suppose that its 12 degrees, wind if 15-20 mph and its 4:30 am. You need to climb a 30 degree slope for 600 feet to get to where you are going. Unless you run unusually warm or you are particularly out of shape, a baselayer may not be sufficient for regulating your body temperature. You might want something to provide a little wind relief and maintain a moderate amount of warmth. A puffy would likely be too much resulting in overheating. A rain jacket, while cutting the wind, may not be sufficient enough in the insulation department. It may also not breathe well enough if you tend to sweat a lot. Something in the realm of light fleece with breathable outer membrane that blocks a bit of wind might just fit the bill perfectly. Could be a vest, could be a light jacket with or without pit zips, may or may not have a hood: All depending on your preferences. Its a layer that is going to provide a moderate amount of warmth so you can be on the move and maintain a desirable amount of comfort in variable conditions that are generally on the cool to cold side of the spectrum.