CASAS.ES is a free, browser-based map with a data sheet for each of Spain’s 12,974,035 buildings. It brings together more than 6.3 million energy performance certificates published as open data by the official registries of 13 of Spain’s 17 autonomous communities and links each one to its building through the cadastral reference.

For every building with a registered certificate, the sheet shows the official energy rating (A to G), the building’s orientation, its estimated energy demand and its estimated annual energy cost, next to the year of construction, floor area and number of dwellings from the Spanish Cadastre. A map filter highlights certified buildings, so the energy performance of a street, a neighbourhood or a whole municipality can be read at a glance. Each sheet also includes a section on the roof’s solar potential.

The tool is aimed at homeowners, buyers, tenants, municipalities and researchers who want to screen the existing building stock before a renovation or a purchase. It needs no registration, works on desktop and mobile, and its interface is available in 21 languages. Every dataset is cited with a link to its official publication at Data sources · CASAS.ES, and the methodology is public at Methodology · CASAS.ES.