Recent Advances in Radiative Cooling Architectural Coatings: From Optical Principles to Building Energy Savings

Radiative cooling architectural coatings reject solar gains while emitting terrestrial heat toward the cold sky, offering a passive route to reduce envelope heat gain and mechanical cooling demand. Its central argument is that high solar-weighted reflectance and long-wave emittance create opportunity but do not, in themselves, establish building value. Climate, sky view, insulation, thermal mass, HVAC operation, weathering, maintenance, and service life ultimately decide whether a surface-temperature benefit translates into a measurable reduction in peak load or annual energy. Accordingly, this synthesis distinguishes optical, coupon, outdoor, envelope, test-cell, and modeled evidence; contrasts hot–dry and hot–humid deployment; and defines a decision-ready evidence pathway grounded in retained spectra, calibrated heat flux, quantified uncertainty, annual energy, cost, and life-cycle impact.