How Can I Reinstall My Alarm System on My Replacement Windows?

Erik Johnson

Replacement windows are a great way to reduce energy costs and increase the value of a building. Replacing windows protected by an alarm doesn’t mean you need to replace your alarm system. Reinstalling sensors is easy to do, and some types of alarm systems won’t require any modifications at all.

Contact Sensors

The most common fixture of an alarm system are window contact sensors. Sensors are a pair of magnets placed close to each other. When the alarm system is active, the sensors detect when a window has been opened and will sound the alarm. In commercial and industrial buildings, these sensors are attached to the inside of the window. The magnets aren’t attractive, so in a home installation they’re integrated into the frame and sill of the window, so as to be invisible. Older sensors are connected to the alarm box by wire, though wireless systems are available. Since installing magnetic sensors is a modification to your replacement window, contact the window manufacturer to get an exemption, so that you don’t void the warranty. Examine the window as it closes, to choose a spot to remount the sensors. Mark your intended spot with a thick layer of lipstick, and close the window firmly to transfer your mark to the sill. Drill into the window and sill and mount the sensors according to the manufacturer’s instructions, or hire a qualified security installer. Test each window to make sure the sensors are aligned properly; this will prevent false alarms.

Vibration Sensors

Windows that don’t open are protected with glass shock sensors. These piezoelectric sensors detect the vibrations caused by breaking or cutting the pane of glass, and are visible to the outside to deter intruders. If your previous window had a foil or mechanical breakage detector, use a piezoelectric sensor to replace it. Each sensor protects a ten-foot radius of glass, so install multiple sensors on larger windows. The sensors have an adhesive backing: Stick them firmly on the window and wire them back into your security loop. When reinstalling shock sensors, contact the manufacturer to determine a replacement adhesive.

Other Systems

Security systems that rely on infrared, ultrasonic or acoustic protection usually don’t need to be adjusted for replacement windows unless the new glass is of a vastly different size or thickness. Test your system after your new windows are installed. Don’t forget to replace the stickers on your windows that indicate the presence of a security system. Warning stickers can encourage an amateur burglar to seek an easier target before he even enters your home or business.