The fact that Shabbos elevators are not assur must imply that those poskim were OK with that extra energy usage for whatever reason.
Some Shabbos elevators are specially designed to use the same amount of electricity no matter the weight inside.
I’ve never understood how walking through the motion sensor on the door is mutar on those.
I would guess that the doors are programmed to stay open for a set amount of time, and that one would need to enter within that time period.
DY: Do any of your sources say that Shabbos elevators are mutar, but escalators are not? I’m curious, because it does seem like escalators would be less problematic.
No, they aren’t specifically addressing escalators, probably because of blubluh’s point, but I don’t see why those who asser elevators would be mattir escalators. To quote the Chelkas Yaakov, ?? ?? ?? ?? ?? ???? ????? ????? ????? ?? ????? ?? ???? ?????? ????? ????? ????? ????? ????? ?????? ???? ??, ???? ????? ??? ?????, ?????? ??? ????? ?? ???? ????? ?????? ?? ????? ?????, ??? ?????, ??? ???? ?? ???? ????? ????? ????? ????? ???? ????? ????? ?? ??? (?? ??? ?????? ???? ?????? ?????, ??? ????? ?? ???? ??? ????? ??????) ???? ?? ?? ????? ??? ?? ????? ????
Although his words were said to compare an elevator to a train, the same could be said for an escalator.
BTW, rabbiofberlin, earlier in the teshuvah, he specifically says that he is also addressing automatic elevators:
??? ????? ?? ????? ???? ?????? ????? ?????? ???? ?????, ???
??????? ?????? ?????? ?????? ?????? ????? ????? ???????, ?????? ???? ???? ????? ????? ??????? ?? ??? ???? ???? ???? ???? ??????? ???