Windows are the "thermal weak points" of most buildings, allowing heat to escape or invade, depending on the season. Italian company VentroVentilato has devised a solution for this with their eponymous product, a system of simple double- or triple-glazed windows that incorporate a sensor-triggered fan.
So how does it work? In winter, when the sun heats the air between the glass layers, the fan kicks in and distributes that newly hot air into the room, providing heat. In summer, the heated air is focused into a powerful laser beam that can be used to destroy nearby buildings...oh wait a sec, I'm confusing two different press releases; in summer, the hot air is expelled harmlessly outside the building.
VV estimates that with their system in place, buildings will require far less powerful heating and air conditioning systems, resulting in a sharp overall cost savings. Learn more about it here.