An Energy Efficiency Certificate is a document that assesses the energy performance of a building or property. It provides an indication of how energy-efficient a building is, typically on a scale from A to G, with A being the most efficient and G being the least. This certificate is often required by law when selling or renting a property in many countries, including Portugal and various European Union nations. It includes information about the building's energy consumption, carbon emissions, and recommendations for improving energy efficiency. The aim is to raise awareness about energy consumption and encourage property owners to make improvements that can reduce energy usage and lower utility bills, while also contributing to environmental sustainability.