Sun films have been available commercially for a long while. Choose how much sunlight you want reflected (generally more in bedrooms that you generally want dark and cool, less in rooms where you want a view), and either get a professional to apply or do it yourself—it just takes a bit of soap water and effort.
Generally better to have the sun rejection happen on the outside of the window, so as little as possible energy gets absorbed.
xxce2AAb@feddit.dk 2 days ago
I suppose I could paint my windows with yoghurt. Or, and hear me out: I could eat the yoghurt and invest in some white curtains.