The EFFESUS project was devised to reduce the environmental impact of Europe’s valuable urban heritage by making significant improvements to its energy efficiency while preserving its cultural and historical values.

This publication presents a practical guide on improving energy efficiency in European historic urban districts, developed through the EFFESUS project, which combines technical innovations, decision-support tools, and case studies to balance heritage preservation with sustainable retrofitting. 

A structured organisation and categorisation method for historic districts was devised based on the state of the art of existing district modelling and categorisation, with two new aspects added. The first aspect is that the method developed within the EFFESUS project allows for flexibility, which helps the categorisation, given the amount of data available for the specific district. The second aspect is that the method includes an impact indicator that accounts for heritage values in relation to energy interventions.