Hello Fernando, This is a difficult to answer correctly. I hope you get better reply from other members. I tried my best to answer for you as follows: 家(うち) means "my" house when I say. For examples, うちにおいでよ　Please come to my house. うちはちらかっている　My house is messy. But うち doesn't mean always "my house" If it has "きみの" together. For example, きみのうちのはあたらしい is "Your house is new" 家(いえ) means just "house". So you need to put suffix "-no" as case particle to show "my" "your" "his" "her" or "their". 　ぼくのいえにおいでよ。 Please come to my house. 　ぼくのいえはちらかっている　My house is messy. きみのいえはあたらしい　Your house is new. Hope this helps.