CAVEAT: I am not a rabbi and I don't play one on tv.
The Question: If you live in a high rise building, high enough that people on the sidewalk in front of the building cannot see anything in your window, where do you put the hanukiah?
What's a "hanukiah?" It is Hebrew for the Hanukah menorah.
According to the late leader of extreme haridim in Israel, Yosef Shalom Elyashiv, there is no value in placing a hanukiah in the window since he determined that no one at street level can see the hanukiah or the flames.
The late leader of Shas, Ovadia Yosef, agrees with Elyashiv and rules in one of his books, Yalkut Yosef, that the proper place for the hanukiah is opposite the mezuzah on the front door. This was the traditional position of the Hanukah lights in the days of yore.
There are other opinions that DO say to light in the window to advertise the miracle to the folks across the way who can see the high rise apartment's window.
Since Hanukah, like Purim, is "post-Torah" the only rules for where to place the hanukiah are "d'rabbanan" - by the rabbis.
The whole idea of the hanukiah is to advertise the miracle.
While causing a fire in a high rise building would most assuredly make people aware of Hanukah, I seriously doubt that it the type advertisement the rabbis of old wanted. Besides, in most high rises, a real fire, especially an unattended fire, in a hallway would be discouraged at best and likely illegal in any event.
Rabbis Elyashiv and Yosef not withstanding, it seems safer and more sensible to put the wicks on the window ledge where there is a chance they will be seen without endangering anyone.
It should go without saying that curtains and anything else flammable must be kept far aware from the flames, but in a time when a cautionary label on a sleeping pill must state "May cause drowsiness," maybe the obvious isn't quite so obvious to all.
The minimum height from the floor for a hanukiah is roughly three handbreadths. According to the rabbi of Nahar Shalom in Dania Beach Florida, a hanukiah sitting so low shows that the lights are only for the holiday; the flames are too low to be useful for any function other than to look at and enjoy. The only problem with that is unless the building has floor-to-ceiling windows, no one passing by will see the lights.
Where I live - Hollywood FL - we are expecting continued winds of 20 mph, with gusts to 35-40 mph. Unless I can build a wind-proof hanukiah (maybe 8 lanterns with a hurricane lamp as the shamash), the flames of an across-from-the-mezuzah hanukiah would stay light about 3 seconds - 29 minutes and 57 seconds too little to satisfy the rabbinical requirement.
In any event, the south Florida minhag for mezuzot are to put them inside the door, rather than outside. The reason: thanks to hurricanes, Florida requires that doors open outward - hurricane winds will force doors closed. We don't normally have storm doors or mud rooms protecting the entrance doors. (See Minhag "Florida" elsewhere in this site.)
The bottom line: The hanukiah and the lit wicks have two purposes:
One: To advertise the miracle to the world, to both Jews and non-Jews alike.
Two: To give us some visual pleasure, "us" meaning everyone in the family, including the women who traditionally do no work while the flames remain.
חג חנוכה שמח
