Here in Washington state you don’t need self-defense to be justified in shooting them. From the facts so far it doesn’t sound like this shooting wasn’t justified - the guy should have called the cops. Then waited outside to keep the guy around for the arrest. Or - could have made a citizen’s arrest.
In Washington state you can shoot a guy running away from a felony. Breaking and entering is a felony. However, while the law might be on your side, I wouldn’t shoot a guy even if he did break my door and use all my hot water. And some DA might try to make a name for himself and argue that the law doesn’t apply in this case.
In Washington you can use deadly force to prevent a forcible felony. This wasn't a forcible felony, and it wasn't being prevented.