Looking for additional security and/or keeping the cold out or heat in, you cant go past a window roller shutter.   Window roller shutters come in a number of different formats, from manual, 240v & 12v control. We just finished installing these roller shutters on all windows in Hobart using the 12v system.  Depending on size these can lift up to 40 lifts between recharges. This will keep out the noise from traffic and recent developments that have started, providing additional security and heat retention in winter months.  Window roller shutters have a foam core, that is designed as both internal and external heat barrier.