What temp do babies need the house kept at?

👪 5/6/2016🚜👣
We have propane, which is expensive to fill the tank, so as of now we suffer through the winters, sometimes our house is 50 degrees... OBVIOUSLY the house can't be that cold when baby arrives, but what's a recommended temp? Like minimum, I don't want baby to be freezing, but I honestly can't stand the house when its like 72+