The pipe freezing thing used to be pretty common here, but for the last few years, it hasn't really gotten down to freezing very much at all. The weather has definitely changed here, we used to be covered in fog this time of year. The other night, we picked up our son at the airport, and saw just a few whisps of fog, but nothing that impeded visibility.I've lived several places with un-vented space heaters. (Dearborn and other brands) the "saving grace" was that our homes back then were nowhere near as "air tight" as they are today. The house I'm now in (for 28 years) is the first I ever lived in as an adult with forced air central heating. Pretty efficient unit, so not excessively expensive to run. I keep the thermostat at about 67° F all the time. (in winter) That's a little chilly for some, but if I get cold I'll just put on a hoodie.
My mom always said growing up, they turned off heat at night. She didn't know if it was for safety or "cheapness". On super-cold nights, I wondered if they ever had pipes freeze? I did in my previous house.....and it's a real pain.
I have my outside pipes wrapped with insulation, and that has been enough so that we haven't ever had a problem even when it froze here. That doesn't mean we couldn't have a problem just that we haven't.