AbstractBuildings use as much as 40% of the world’s total primary energy. This huge energy consumption is mainly tied to poor designs and entrenched practices for buildings’ envelopes. One major road toward more energy efficient buildings is to employ design principles that are in harmony with the radiation in our natural surroundings. Glass coatings with spectral selectivity can lead to windows and glass facades with good thermal insulation and capability to transmit mainly visible light or, alternatively, across the full solar spectrum. Chromogenic glazings, especially if based on electrochromism, can regulate the inflow of visible light and solar energy between widely separated limits and achieve further energy efficiency. The new fenestration technologies are able to improve indoor comfort.