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Most home break-ins occur when the occupant is out. The burglar "cases" the house to be sure that you're away, then typically breaks in and quickly steals whatever valuables happen to be easily accessed. Much more serious are home break-ins when the occupant is present, because these can lead to physical assaults.
You may find this hard to believe, but day time break-ins are quite common now, much more so than they were just a few years ago. We can only assume it is because no one stays home much in the daytime. It is easy to kick in a door, grab what you want and leave. Chances are good no one is at home next door or across the street either.
The most common response when a home break-in occurs in a neighborhood that has previously been relatively crime-free is for homeowners to create a "fortress house." The idea is to physically stop intruders. This can be more or less successful, or desirable, depending on the approach.
Window/Door Bars
This is often considered the ultimate home protection by people who live in high crime areas. There are always companies (check the Yellow Pages of your phone book) who are eager to install these on your home.
Barring up your house does make it more difficult for the "spontaneous" criminal, the one who picks a house at random, to burglarize. It's not clear, however, that bars will keep away a truly determined assault on your home.
Barring your house, however, does carry with it at least two concerns. The first is appearance. If you ever hope to sell your home, having bars on the doors and windows, no matter how attractive they might be, is a sure turnoff to buyers. Buyers will immediately assume, perhaps correctly, that yours is a high-crime area and will look elsewhere. In order to sell, you might have to accept a lower price.
Even if you don't have bars on your windows and doors, if your neighbors do, it tells the same story to would-be buyers. Yours is an unsafe place to live.
The second problem has to do with your personal safety. There have been countless stories of people who have burned up in home fires because they couldn't get out through barred doors and windows. It's important to remember that both doors and windows are portals, routes of egress from your home in an emergency. (Most building departments, in fact, insist that all bedrooms have windows built at least a minimum size in order to allow occupants to quickly break them out and escape in case of fire.) For this reason, some building departments will not allow windows and doors to be barred. Or if they do, the bars must have devices that allow them to be quickly retracted.
If you're considering barring up your house, don't just look at it from the perspective of someone trying to get in. Also consider how difficult it might be if you need to get out.
This article continues in Basic Security Measures Window and Door Locks.