In Portugal, an Energy Performance Certificate (Certificado de Desempenho Energético, or CDE) is a mandatory requirement for all properties being sold or rented. The certificate rates the energy efficiency of a property on a scale from A+ (most efficient) to F (least efficient), based on factors such as insulation, heating, cooling, and overall energy consumption. This system helps potential buyers and tenants understand the property's environmental impact and operational costs, allowing them to make more informed decisions. The CDE must be obtained from an accredited professional who assesses the property.

The Energy Performance Certificate is part of Portugal's broader efforts to reduce energy consumption and carbon emissions, in line with European Union directives. For property owners, having a higher energy rating can increase the attractiveness of the property in the market, especially as energy efficiency becomes an increasingly important factor for buyers and tenants. Additionally, energy-efficient homes may benefit from lower utility bills, making them more desirable and sustainable in the long term.