"This seems almost impossible to implement successfully. How would you define "spends very little time there"? And how would you go about enforcing it, proving one way or the other that an owner was "living" there for that amount of time? Does it count if I, the owner, am rarely there but I let friends and relatives use it for much of the time? You might be able to construct a tax around non-primary residences, but I wonder how that would effect landlords and the rental market. In the end it doesn't do much to solve NYC's housing problem, which is that there's too little supply to meet the demand. Build a few million more houses across the city's five Burroughs to lower the prices, and a couple of empty ones won't seem like such a big deal." - Eric P