re: #179 Teukka

So you have a hot water pipe that goes from the heater/furnace to the kitchen, but no return pipe(s) to the heater/furnace?
Most homes in these parts have what’s called Varmvattencirkulation (Warm Water Circulation), where you have a return pipe for the hot water (mine goes through a tower heater in the bathroom (not allowed these days, has to be direct return))) to keep the hot water hot, and to prevent spots where you can get Legionella.
Could be an idea the next time you have to do plumbing work, tho no idea how economical it’d be, but it would prevent pipes freezing.

Our furnace is a floor model Montgomery Ward run by natural gas. It does not use water.

Water comes in from the mains from the front of the house to the back, where it then splits up to the various spickets. The hot water heater was new when we bought the house, but the staircase to the cellar is too small so the installers had to cut a hole in the kitchen floor to put it in (I really hope we never have to replace it).