Scott, good to see you back again.
I tend to view heaters in roughs as being a spot to wander over to, to thaw out the hands and feet real quick so you can function.
My recent changeover to commercial has opened a whole new perspective on cold - romex and wood floors/wall framing are much less brutal than concrete and steel structures working with EMT. It's as though they are designed to suck the heat from your body.
All things being equal, I'm acclimated to sub-30 degree days now, so the thought of buying a heater for highs in the mid-40's is laughable, IMO.
If the temperature drops below 10, we've got alternate jobs to work at, thankfully, because that's when it really gets hard to stay productive. When that sensation comes along that the drip in your nose has frozen before it's gotten out,
that is cold.
I bought some composite-toed Redwing boots, I've been wearing two pairs of socks, and have been going through insulated gloves like crazy. The biggest help against the cold in my experience is simply long underwear, it's amazing how much a couple layers on the legs helps with the overall misery.
On the commercial jobs, the salamanders are most common around here. When in resi, I had a standing unpowered propane burner (advertised itself at 100,000 BTU) that thawed hands and feet in a hurry, but tended to freeze up a small five-gallon tank quickly. A larger tank is needed to keep it burning for an extended period.
For forty degree days, mechanic's gloves (uninsulated) keep blood in the hands in my opinion, and provide more dexterity.
