Frozen paintballs for home defense?

I see, a decent Idea.
BUT
1. Do you have time to reach the Freezer to get them.
2. Will the frost on them jam the gun.
3. Can you hit the person in unprotected areas causing sufficient pain to prevent them taking you apart and jamming the remaining balls down your throat.
4. Locking yourself in a safe room and calling the Police would do you much better.

So when someone breaks into your home you ask them to wait while you go to the freezer for the frozen paintballs?

Not a good choice. You're better off with a hunting slingshot and metal ball bearings.

You would die.

they're called 'painballs' and it was the invention of some kid in the late 90s and while it can cause alot of pain and probably knocked out teeth, is not good for defense as it can open you up to civil and criminal liability, and not effective against someone who is aggressive and violent.

they're also very unreliable, they don't freeze evenly resulting in non-ball shapes that can jam your gun, the freezing weakens the plastic shell and the paintballs are known to rupture and screw up your gun, if you get them to work they're quite inaccurate and have limited range due to uneven deposits of ice, and getting them to freeze without bursting or cracking is quite difficult.

painballs originated from the eastern us around 1997. it was a thing for the older kids to shoot younger kids new to the game with frozen paintballs. often times it would cause serious injuries requiring emergency medical attention.

however, you need to look at the situation. children are not adults. those kids went to the event with intent to have fun. home intruders generally are of at least adolescent age, they are stronger, tougher, have more tissue that cushions vital organs from trauma, and intruders/attackers have a different mindset than kids playing. mindset makes a huge difference in how injury is interpreted by the brain, and with mindset to cause harm, minor injury signals do not deter behavior, it may fuel motivation to carry out action. meaning if you shoot an angry man with this, it'll only make him madder.

You are looking at this wrong. You speak of taking someone down and of home defense.
If someone breaks into your home, they have already considered what to do if you are home. He may have decided to flee in which case you only need to yell at him. If he is intent to forcibly deal with you if you are home, your only real choice is to "take him down" reliably with one shot. Hiding in the closet and calling police means the police will arrive to find you dead and the bad guy long gone.
.45 ACP in a gun locker next to where your bed is my suggestion. If you can't or won't do this then move to a better neighborhood.

Only if you get them in both eyes.

Frozen? You realize that they would be hard, right? They could very easily kill.

Spend the money for pepper balls. They have a dry form of pepper powder in them that is similar to pepper spray. The police and others use them. If you have the know how, make your own. You can even use the liquid form, like pepper spray, in them like paint.

My guess is, if you target the right areas, even the regular paint balls will do it. Shots to the groin, for males, should do the trick. Kind of hard to kick a ball flying at you the size of a quarter.

I doubt it

kind of like the difference between a door with a run of the mill lock and a door with a lock, deadlock and chain

just means I have have to use a lot more force to enter

if you want to "stop" someone youll be wanting a steel door with a properly fitted frame and a real weapon