The European building stock is mature, and expanding cities need inclusive and innovative renovation solutions for all citizens while intensifying city densification. The European project EU-GUGLE aims to reduce primary energy consumption by 40-80 % and increase renewable energy use by 25 % through nearly zero-energy building renovation models for initiating large-scale, Europe-wide replication in cities and communities. About 200,000 m2 of residential and public buildings are being refurbished by implementing a balanced mix of technical, socio-economic, and financial solutions adapted to local needs. Six EU partner cities are participating, each revitalizing an urban district: Aachen, Bratislava, Milan, Sestao, Tampere, and Vienna. The comprehensive integrated approach used in EU-GUGLE is in line with the European Smart City initiative, and each participating city has created nearly zero-energy Smart City master plans based upon lowest-energy thermal renovations coupled with innovative renewable energy services incorporating every aspect of smart district life. All stages of the planning, construction, and post-occupancy phases of the large-scale district renewals are being documented, monitored, and evaluated to create sustainable district renovation methodologies for "smart renovations for smart cities" to meet the objectives of the European Commission's Smart Cities and Communities Initiative for reducing greenhouse gas emissions by 40 % within the European Union by 2020. The paper outlines the approach each city has taken and highlights case studies of the individual solutions created in three of the six cities.