Well, you suggested me household and since English is not my first language I thought that that was the correct word, but it isn’t.
House in Spanish for example can mean a building, or an apartment, and I thought it also did in English, but after searching for a bit, for building it can’t be used as apartment. In any case, in the way OP used the word it’s clear to me that they mean that all the windows are of the same owner/big apartment, instead of being apartments of separate owners. Have a nice day.