I am new at this, so maybe one of the experts will correct me ... but I would set the elevation for where the barometer sensor is mounted. If your street elevation is 399' and the floor of your 2nd story is 10' higher and your have your barometer mounted 5' up on the wall of the 2nd story, that would make the elevation of the barometer 414'. From some of the barometric pressure charts I have looked at that could make a difference of ~.01 Hg. Not a big deal, but I guess I am kind of perfectionist.
I think some people make a mistake of using the elevation of their ISS (including height of the pole) when the barometer is actually in the console or smarthub. But again, I am just learning, so I could be completely wrong.
I think some people make a mistake of using the elevation of their ISS (including height of the pole) when the barometer is actually in the console or smarthub. But again, I am just learning, so I could be completely wrong.