It was worse when I was a kid, in winter we had to heat the house to blistering on friday afternoons and just hope it stayed warm enough til sabbath ended (if it wasn't, we had to get a non-Jewish friend to come turn the furnace on for a bit, and there was all sorts of rules about whether that was allowed too). And if you turned a light off at night by reflex, it stayed off. Nowadays there's all sorts of "sabbath mode" gadgets lol