>just closes a pair of contacts that tell the boiler "heat on" or "heat off" and it's not "literally starting a fire" in your house

Unless you observe Shabbat.

https://en.wikipedia.org/wiki/Electricity_on_Shabbat

>Nobel Prize-winning physicist Richard Feynman recounts that he was approached by young rabbis in a seminary who asked him "is electricity fire?". He replied, "no", but asked why they wanted to know, and was shocked that they weren't interested in science at all, but just wanted to interpret the Talmud. Feynman said that electricity was not a chemical process, as fire is, and pointed out that there is electricity in atoms and thus every phenomenon that occurs in the world. Feynman proposed a simple way to eliminate the spark: '"If that's what's bothering you, you can put a condenser across the switch, so the electricity will go on and off without any spark whatsoever—anywhere.' But for some reason, they didn't like that idea either".

Feynman was SHOCKED I say SHOCKED they weren't interested in science at all! ;)