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.
It’s not obvious that it’s the same house. House doesn’t necessarily equate building. People use house and home interchangeably, and in an apartment complex “house” can refer to a single apartment. Thus, when saying that it’s the same house they are saying that the same person owns those apartments. You might not agree with that definition of house, but that clearly what the OP is using.
It’s not that expensive, here a package of Twinnings Earl Grey costs like 4-5€, and it comes with 25ish teabags. If they really like it, 50 for 150 is 15 times cheaper than what they were paying before so idk.