Here, we develop a dual-band electrochromic (EC) smart window by integrating reversible Ag electrodeposition/dissolution with mechanical flipping. The device enables dynamic modulation of both the solar spectrum (0.3–2.5 μm) and mid-infrared (MIR) spectrum (2.5–20 μm), allowing reversible switching between radiative cooling and solar heating modes. In the cooling mode, the EC window exhibits a high solar reflectance of 87.9% and a high MIR emissivity of 90.6%, whereas the heating mode provides a solar transmittance of 61.2% and a low MIR emissivity of 10.8%. The device also shows rapid electrochromic switching and good cycling stability. Outdoor measurements demonstrate effective sub-ambient cooling and solar heating. When applied as a building skylight, its global HVAC energy-saving potential can exceed 50% at maximum.

Electrochromic glass,Reversible electrodeposition,Radiative cooling,Solar heating