First order calculations of the relative thermal footprint of adaptive and traditional radiative coolers

Adaptive radiative coolers, like thermochromic and electrochromic thermal emitters, are more energy-efficient than traditional radiative coolers because they do not overcool buildings in the winter. This means that they have a CO₂ emissions reductions benefit from a climate-change perspective. However, because this functionality also inevitably traps solar or longwave heat on earth, adaptive radiative coolers may not be sustainable for building thermoregulation. We show through first order calculations that compared to static traditional radiative coolers, adaptive radiative coolers with switchable emittance will trap more heat on earth than they will help lose by reducing CO₂ emissions, for the foreseeable future. Detailed calculations show that adaptive radiative coolers may have a net heating penalty relative to traditional radiative coolers that lasts beyond this century.