Yes, I would always say "at our house," if talking about what my family does, as in this sentence. I might say "in our house," if talking about the physical layout of the house, e.g. "In our house, the basement has a separate entrance."
Ok, we are learning Indonesians here. You may come across an strange Indonesian sentence in your life of Indonesian language. Let's focus on figuring out the meaning even if the sentence seems meaningless.