Published July 3, 2016 at 2129 × 1605 in Louvre window for summer nights « Previous Next » Louvre Time Clock The power supply for the automated night-purge louvre, with its Hager EG203E programmable Time Switch and relays. Power is switched on only in summer, and the switch is set to open the louvre at 21:00 and to close it at 07:00.