Work-In-Progress. (Sub)ambient is made of densely packed CaCO3 nanoparticles and ultra porous natural cellulose nanofibers. Both materials act like microscopic mirrors, scattering sunlight internally until it is reflected away. Most heat on earth is trapped by the atmosphere, but Infrared radiation at a frequency of 8–13 µm is not absorbed by the gases surrounding earth. The compounds which make up (Sub)ambient emits infrared radiation that passes through this atmospheric window.