Thieves looking to make a score via home invasion will be targeting residences based on one fact: How easy is it to get in? In most cases, the easiest points of access for thieves and burglars will be windows. In most cases you will find more windows left unsecured then doors, but skilled burglars will have no problem breaking the glass if need be. There are several precautions you can take to better secure you windows:
Security Film
Plastic security
film applied to windows stops the glass from shattering and clearing for a burglar to make an easy entrance. While the film will not prevent the glass from breaking, a thief will not risk taking the extra time to try to break through the film. This is often cited as the most popular security measure for windows since it provides excellent protection without sacrificing aesthetics. The only drawback is that unless the film is tinted, a thief will not be able to spot the film until they try and break the glass. Although in my opinion, a homeowner would much rather replace a window then stolen personal effects.
Security Screens
Another option for window security is a screen. These screens resemble your average screen door material, but are much stronger and more durable. Constructed out of steel, these screens are not easily clipped and can withstand heavy blows from crowbars, baseball bats, and other blunt objects. The screens are attached to the outside of the home and can be opened with an interior latch.
Window Bars
If you want to give would-be thieves the hardest time, putting bars over your windows is your best bet. The thick, steel bars will pretty much stop anything trying to get through your window, but they are not very popular due to their unsightly appearance. That being said, bars are perfect for windows into your garage, basement, or other areas where aesthetics are not a huge issue.
Source: http://blog.allstate.com/home-security-tips-for-windows/
By Paul Doh