I've done more 30min-2hr sub-zero F bike rides here in interior Alaska than I can count, as well as many 5+hr rides for things like races and backcountry trips.

I've done more 30min-2hr sub-zero F bike rides here in interior Alaska than I can count, as well as many 5+hr rides for things like races and backcountry trips. Some of the coldest days are at -30F or -40F. I use a simple wool balaclava as well, and it works great. The author here seems weirdly obsessed with the idea of "breathing cold air" resulting in heat loss? While breathing cold air isn't necessarily pleasant, in my experience, if you're actually _exercising_ (raising your heart rate to say, 120 or more?), then even down at -30 you very quickly run into the opposite problem. You're generating a _ton_ of heat from exercise, and you're sweating your ass off. Most of the time I end up periodically pulling my face covering off to help cool down. I'm not above trying one of these, but it feels a bit like a solution in search of a problem. Maybe I'm underestimating the difficulty of the average bike commuter's ride, and they're not regularly getting their heart rate elevated? But I can say that in 5-10 years of winter bike commuting, racing, and backcountry travel, almost everyone I see is using a balaclava, despite these things having been around for a while.