💡Gothenburg University, found a way to turn ordinary windows into solar heaters
You can use the energy of the sun to raise the window temperature to 15 degrees Fahrenheit.
Using nanotechnology, researchers at Gothenburg University created a plasmonic nanoantenna that strongly absorbs light and gives heat to the surface (it is most suitable for glass but anything is fine).
Even when the window glass of the glass is covered with the nanoantenna, it remains transparent and colorless and almost completely preserves the color spectrum of sunlight.
https://www.engadget.com/amp/2017/10/27/solar-windows-use-sunlight-to-retain-a-buildings-heat/