Live and Learn: The Baseboard Heaters

After having a plumber in, again, for various things, he asked offhandedly, "why my heaters were closed in the bathroom? and didn't I want the heat on in there?" It had been very cold in the bathroom. It turns out that the baseboard heaters had mostly been off. For five years. 

So now they are open and on.

Closed and Off.

Open and On.

And now I know.