Questions & Answers about Vårt hus er større enn deres hus.
They are all forms of our, but they agree with the noun:
- vårt – used with neuter singular nouns
- vårt hus (our house) – hus is neuter.
- vår – used with masculine and feminine singular nouns
- vår bil (our car) – bil is masculine.
- våre – used with plural nouns (all genders)
- våre hus (our houses)
- våre biler (our cars)
In the sentence, hus is neuter singular, so you must use vårt.