An air rifle can come in any size and power, comparing with Airsoft at one end, and a 357 magnum at the other. Anything suitable for use as a defense would be capable of inflicting deadly force.
If you don’t want to use deadly force, then the best way is to surrender, and let the intruder do whatever they want, including whatever they want to you and your family. This doesn’t preclude you objecting to whatever they are doing, but you have no power to stop them either way.
Be aware that if this situation is not what you desire, then you need to be capable of stopping them, and if this means you sometimes are backed into a choice between letting them take you or killing them, then this is a choice you will be forced to make.
Having a weapon capable of inflicting lethal force doesn’t mean you have to use it – but if you choose to use it, you can offer the intruder an option to leave or even let them ransack your house if you want. You can threaten to use it. Heck, fire all the warning shots you have to if that makes you feel better. All having such a weapon does is provide you a means of power to decide how much you will allow them to do before you act.
Having a lethal weapon doesn’t force you to kill anyone any more than driving a motor vehicle does ( motor vehicles are also lethal weapons ).
However, when you are backed into a situation where there is no other way, then at least you still have a choice. What that choice is, I’ll leave up to you.
Want a less than a lethal option? OK, get pepper spray. Keep in mind that many attackers probably won’t care much about the spray – it may just antagonize them. Tazers? Don’t always work. I’ve even known one man who used to taze himself for fun each day until he broke the tazer by over-using during a two-minute self-taze.
But a best air rifles? To what? Cause an attacker’s pain and injury? That’s wrong on so many levels. First, it’s just plain ineffective, but from a moral point of view, if it’s not a serious enough incident to justify killing someone, then it most certainly doesn’t justify wounding them.
If you hit the guy in the head, there’s definitely potential to kill, by the way. Especially if you have an air rifle that shoots .357 pellets that breaks the speed of sound. Some people actually hunt deer and even hogs with high-quality break-barrel or pre-charged pneumatic air rifles. If you shoot the intruder in the body, there’s a chance that you’ll puncture a lung, heart, major artery, etc. and potentially kill him, too. You might as well buy a shotgun (cheaper, easier to hit a target, and faster to re-chamber around/shell), load it with birdshot, and hope it doesn’t kill him. I wouldn’t recommend less-than-lethal rounds for shotguns. You’ll either piss him off or kill him.