What energy transformation occurs when solar panels are used to heat a building?

When solar panels are used to heat a building, the primary energy transformation involves converting solar energy into electrical energy through the photovoltaic effect. This electrical energy can then be used to power heating systems, such as electric heaters or heat pumps, which convert the electrical energy into thermal energy, warming the building. In some systems, solar thermal panels directly absorb sunlight and convert it into heat, which is then circulated to heat the building.