Chromic materials can change their colors in response to heat (thermochromic) or voltage (electrochromic). Incorporation of these materials in smart windows enables the intelligent regulation of window transparency, allowing for control of transmitted light and heat into building interiors. This control allows improved energy efficiency and occupant comfort. With the application of heat or voltage, state-of-the-art chromic windows can switch from transparent to opaque and reject unwanted solar energy as heat. However, the National Renewable Energy Laboratory’s (NREL’s) chromic photovoltaic (PV) window technologies can transform a portion of the rejected or transmitted energy into electricity, using perovskite materials commonly found in PV panels of traditional architectures. To switch the transparency state of NREL’s chromic PV, heat or voltage trigger molecules to absorb into or desorb from the perovskite structure, causing a reversible change in bandgap properties.