Okay folks, here's the deal on Ohio's self-defense law. In Ohio, self-defense is an affirmative defense. In other words, it is something the defender must prove at trial (or beforehand, if you're a lucky person and the prosecutor is good). To prevail on a self-defense claim, the defender must prove that (1) the defender was not at fault in creating the violent situation, (2) the defender had a bona fide belief that he/she was in imminent danger of death or great bodily harm and that only means of escape was the use fo deadly force, and (3) that the defender did not violate any duty to retreat or avoid the danger. State v. Robbins (1979) 58 Ohio St.2d 74. If a person in good faith and upon reasonable grouind believes that a family member is in imminent danger of death or serious bodily harm, such person may use reasonably necessary force to defend the family member to the same extent as the person would be entitled to use force in self-defense. State v. Williford (1990) 49 Ohio St.3d 247. While there is a duty to retreat when there is a reasonable means of retreat available to escape the confrontation, there is no duty to retreat from one's home. Williford. Deadly force may not be used to protect mere property. (Can't find the case right now).
So, what does this mean? IN your home, in reasonable fear for your life and/or the life of a family member, you'll probably prevail on a self-defense claim. Go looking outside the home for the source of a noise, you're defense will get weaker, but you'll probably prevail. However, since this is an affirmative defense, you'll basically be admitting guilt, but arguing that there is a legal excuse or justirfication for your actions. You need either the prosecutor or the jury to agree with you to prevail in the long run.
And let's not even get started on the civil case that will come...