Some home defense alternatives

[Speck Tater]

160. Probably the best first line of defense

is having a door that can't simply be kicked in.

The longer it take for someone to break down your door and get in, the longer you have to hide, get away, lock yourself in a panic room, set off a loud alarm, call the police, or whatever.

Priority one: Make your home uninviting to burglars or invaders. Lights, alarms, close neighbors that you know well.
Priority two: Keep the invaders out for as long as possible. Hardened doors and windows, heavy-duty bolts and bars.
Priority three: Have a place to go when the bad guys start trying to gain entry. Panic room, hidden compartment, hidden exit to the outside.

If you never come face to face with the bad guys you will be in a much better position of safety. If there is shooting to be done, better to let the police come do the shooting. In the mean time, get away and stay away. Run and hide. Don't let the bad guys see you, or find you.

Another idea is a sound cannon. From the Wikipedia article on sonic weapons:

Extremely high-power sound waves can disrupt and/or destroy the eardrums of a target and cause severe pain or disorientation. This is usually sufficient to incapacitate a person. Less powerful sound waves can cause humans to experience nausea or discomfort. The use of these frequencies to incapacitate persons has occurred both in counter-terrorist and crowd control settings.