Security System Techniques – Protecting Double Hung Windows
Double hung windows are the ones that slide up and down to open. There are several ways to gain entry to this type of window. The first way is to simply pry it open with a crow bar. When this is done, the two small locks that typically are between the two panes, often pull out, as they are normally only attached with a couple of small screws. In this case the glass does not break and therefore a window contact is the primary method of detection. Surface mount contacts are often used with new windows to avoid drilling holes that might otherwise void the window warranty. An interior motion detector can detect the intrusion, after the intruder has already climbed through the window and started moving within the house. More information on types of window contacts will be given in another posting.
The second entry method would be to break the glass to get to the latches to open the window. This is done because the glass is open very sharp and the openings are often a little tight for crawling through. In this case, either a glass break or window contact would work. The glass break would go off first, followed by the window contact and as always a motion detector would detect the intrusion after the intruder was inside. That leaves crawling through the broken window pane as the third option. In this event, only the glass break detector and motion detector would pick up the intrusion.
From a deterrence point of view, security system stickers might help as well as making sure that the window is well lit and not hidden by tall shrubs. From a denial perspective, windows with automatic stops help prevent the window from being slid open too wide. In some cases, people will drill hole and insert a nail to prevent the window from opening too far.