Brought back some memories. Some years ago, maybe 1988, I had a rented store. I had baseboard electric, and you can only begin to guess how expensive that is.
One day I noticed that one store room was warmer than I thought it oughta be, and somehow the heat was on, but low. I turned off the heat, and figured I saved a bunch of money.
Next morning the one pipe was frozen. If memory serves, it was the hot. Can't explain that. I pushed up the ceiling tiles, and after quite a while I did find the frozen spot. The building had used to be a one bay service garage. Along the right side of the building there was a window I'd never paid any attention to that. It was over the ceiling tiles. And it froze right next to the window.
I ran an extension cord, and thawed it with a hair dryer, adn very glad to have that thawed, without any split or leak. I crumpled a bunch of news paper to pack in the window.
The other frozen pipe experience that comes to mind was a customer in a rural farm house. Weather was about 5F, and blowing cold. Really totaly bitter weather. The water heater was fuel oil fired. The pipe came off the W.H. and ran horizontal right across the back of an old slop sink (laundry tray). Right behind that was a double hung window. The sash was loose, and there was bout 3/8 inch crack between the sash adn the top part.
Fortunately, I was able to thaw that pipe witht he heat from my hands. I did have a torch, but it was up a flight of stairs, and out a long walk to the truck. I took some zip screws (got a bottle of th ose in my tool box like most heating guys) and secured t hat sash quite a bit. That couple screws to tighten the window prevented any more refreezes.
the old counsell still works. Leave a faucet dripping at the farthest part of the house.