Hi – I have standard double hung windows. I initially put the 5816 contact sensors for my system at the bottom where they’re not easily seen from outside, but they only protect the lower sash. Getting in through the top of the window seems less likely but I suppose not impossible.

I tried moving the sensors to where the upper and lower meet and cover both halves with the same sensor, but the magnet can barely fit, so once the bottom sash moves up, it pins the magnet to the sensor and doesnt trip it. I tried drilling it in, but the 5816 magnet has internal screws with the magnet on top. So even with the bracket drilled the magnet detaches and gets lifted up. Im thinking at the moment, I can either buy a different magnet with external screw bracket wings or find some way to permanently lock the top sash (if that is possible? so far I found these but likely they would be accessible from outside ).

Any tips would be helpful.

Thanks