Is it illegal to record a conversation with someone if it was in your own home?

Pretty much my house was burglarized yesterday I had a suspicion of who it may be. Today that person came to my house and pretty much made a full confession I was recording him on my iPhone. Is this evidence usable? He also brought back one item that had been stolen is that usable as evidence?

Yes. ESPECIALLY if you're in your own home. Since that's a private residence, the other party would have an "expectation of privacy" and you can't record them without permission.

Call the police and report what has happened. The fact that this person returned stolen property to you is evidence that he had something to do with the burglary. I'm not sure if the recording of your conversation is evidence, but tell the police and let them decide. You don't want to take the law into your own hands.