This Solar Powered Window Alarm by Smart Solar is an easy to install system to add extra security to your home without incurring any long term running costs.
The Solar Powered Window Alarm can be placed anywhere, though obviously it is best placed somewhere to take maximum possible benefit of the daylight there. Designed to be mounted onto the window to power itself through its built in solar panels, this alarm comes with sensors that can be placed up to 60cm away from the main unit due to the adjustable wire it is attached to. The solar energy is stored in a Li-on rechargeable battery supplied.
The Window Alarm produces an alarm noise at 6.8 khz which should easily wake you up should anyone open an alarmed window and trigger it. The only concerns would be its usefulness, as if a window is broken rather than opened it should not produce a sound. Additionally, it would appear that there is no way to tell how much power is stored in the alarm or for how long the charge will run. This leads to some concerns on if it would last a whole night, especially in the long nights of winter where the daylight can also be diminished for days.
The Solar Powered Window Alarm comes as a twin pack for £24.99.