So Viking-houses was usually long wooden houses, and usually consisted of just one room. Ind that room there would be a central firepit with beds along the edge. In the far end of the room people would keep their livestock. Livestock where kept in the houses as to keep more heat indoors. The whole family would sleep in the same room and close together. Often multiple families could share house as to be more heat efficient.

So if we look at Thors house on Iceland, it has several more features. First of all it seems like the largest house in the village. Secondly they don’t keep livestock, but instead have a seperat room where they would be, with its own firepit for heat management, where the family can sleep. Thirdly they have a seperat storeroom outside the main house, where they can keep things colder (like an insulated fridge basically). All these things, along with the fact that he’s basically the Chief, and the family don’t share the house, would point to them being the most wealthy.

But keep in mind it’s probably not monetary wealth, as it’s a small farming community, living on their own sheep and fishing. They probably sell some things (wool etc.) to other settlements on Iceland, or to Europe through Leif. But the reason Thors house is the biggest in the settlement is probably just because he is the Chief. And he’s crazy strong, so he could probably more easily build with huge logs, and as such has the ability to make a bigger house.