The big shot who owns your house is your landlord or landlady.

You'll often hear this with the name ender さん, as in 大家さん, to respectfully refer to the landlord or landlady.

This word uses kun'yomi readings for both kanji. You learned 大's おお reading with 大きい and 家's や reading with 空き家, but here's a mnemonic in case you forgot:

When your landlord asks for the rent, you say, "Oh yah (おおや). Oh yah. I have it, and I'll get it to you pronto. Oh yah, don't you worry." Then, you pretend not to be home for the next few weeks.