A house is a type of building: http://blogs.murdoch.edu.au/arielcohen/files/2011/05/haunted-house-original.jpg 'Home' is a concept, that describes where someone lives or belongs to. Any place (no matter the building type) where someone lives can be described as a home. People also use it to mean anywhere where they feel like they belong. You often hear people refer to their country or their city as their home. This usage is entirely correct. There's a song called "I still call Australia home" http://www.songlyrics.com/peter-allen/i-still-call-australia-home-lyrics/

They can be used interchangeably to refer to someone's dwelling but house usually refers to a building and home is the place where someone lives (which does not have to be a house). Examples: This house is my home. A bird's nest is its home but is not a house. A house can always be a home, but a home is not always a house.