Tom Shafer

Window locks: Are you sure they're secure?

August 05, 2013

When you engage the locks on your windows, are you sure they are actually secure? While the cam lock in the middle of the bottom sash is engaged, the window cannot be opened easily--but it can be opened. How can you provide more security?

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The American Architectural Manufacturers Association (AAMA) requires that windows and doors pass a forced entry resistance test to certify how well they resist entry while in the locked position under conditions of stress and load. Hundreds of pounds of pressure are applied to force them open until they fail. Then they are graded -- the higher the grade, the greater their ability to resist entry. Windows that earn a Gold AAMA Certification are usually very difficult to open. But remember, with enough force the locks eventually do fail the resistance test.

In neighborhoods where there has been a rash of break-ins, police typically advise homeowners to install secondary locks so their windows cannot be opened by force.

2 types of security locks for windows

A metal clamp lock clamps to the frame of the window above the sash. When in place, a would-be intruder cannot raise the window sash. If a pry bar is used outside the window and your window sash lock fails, this clamp remains secured. This particular lock is designed for vinyl windows, which are not all the same, but with a few adjustments it can work on most vinyl windows -- single-, double-hung, or sliders.

window security clamp lock

clamp lock

vinyl window security lock

vinyl window lock

The other security lock is similar, but it operates with a thumb screw instead of a clamp. It also attaches to the frame, but works better on aluminum windows -- the thumb screw can dent vinyl.

aluminum window security lock

thumb-screw window lock

Many replacement windows offer vent latches--sometimes mistakenly called security locks. They allow a window to be opened up to four inches for ventilation. They should not be considered secure as they can be forced open easily.

The use of security locks may keep an intruder from getting in, but remember, it can also prevent you from getting out in a hurry if there is a fire and the window is your only means of escape. Lock your windows, but be ready and able to disengage the lock when necessary.

About the Author

Tom Shafer has decades of experience in window sales, marketing and product development. He's worked closely with window design engineers in testing, design, and building code interpretation. Past employers include United Windows and Doors and Norandex, MI Windows. He currently works at a home improvement retailer.

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