Door and Window Defense
The big difference between door and window defense and an interior barrier defense is the amount of preparation or warning time. The only time you should use a spray defense to stop an intruder from coming through a door or window is when the intruder is already in and you're in imminent danger. A good example would be waking up to find an intruder climbing in through your bedroom window or actually in the residence.
The tactic you should use for window defense is similar to that of pepper spray defense during a personal attack on the street. However, you will not have a place to retreat. If you catch an intruder coming through a window, or if he's already in the residence, spray him directly in the face, then get out of the room, either to a another room or to a hallway. Shut doors behind you if possible. If the intruder comes through the door, spray him again and leave the house. The exception to this is if you have children or other residents in the residence that must be protected. In that case retreat to a position where you can defend them from the intruder should he press the attack.
Use any means available to you to warn the others and facilitate their escape. Spray defense at a door is much the same as at a window, as you directly spray the intruder as he enters the residence. Don't try to open the door suddenly, spray the intruder, then shut it again. Like the street assault, you want the spray defense to take the assailant/intruder by complete surprise. If you spray an intruder and surprise him as he comes in, the chances are good he'll immediately run away.
If the intrusion takes place at night do not turn on the lights if the intruder is inside. If he's still trying to break in turn the lights on. This will probably scare him off which is exactly what you want. The best form of preparation for defending against an intruder is to rehearse what you should do in various situations. This rehearsal can be very effective, particularly if you find you have to use a spray defense in the dark. It's very important to include all residents in the procedure and practice drills.
As mentioned previously, the best type of pepper spray to use for residential defense is a large fogger type. Their range is usually about 15 to 20 feet, and they emit a fine mist, remaining in the air for several minutes. Living in the residence for the next few hours maybe uncomfortable, even after you've washed the area down and aired it out, but that is far better than becoming a victim of a violent assault, which has effects that can last a lifetime.