MEZeroE is an EU distributed open innovation ecosystem for: (i) developing nZEB Enabler Envelope technology solutions ; (ii) transferring knowledge; (iii) matching testing needs with existing facilities; (iv) providing monitoring in living labs and; (v) standardizing cutting-edge solutions coming from SMEs and larger industries, to foster inclusive change in the building sector, being accessible via a single-entry point to all users. MEZeroE allows the development of ground-based solutions focused on carbon neutrality and healthy indoor environment, validated with advanced assessment methods and services, recognized protocols and long-term vision to embrace industry 4.0 trends, rapid decision making and customer-centric requirements. MEZeroE accompanies enterprises in adopting the open innovation approach comprising discovery (phase 1), empowering (phase 2), and exploiting (phase 3). MEZeroE will be accessed via a single-entry point web-based multi-side virtual marketplace, including 9 Pilot Measurement & Verification Lines (PM&VL) and 3 Open Innovation Services (OIS) covering training, business model development, systematic IP and knowledge management. MEzeroE will fast-track prototypes to the market as fully characterized products. MEZeroE virtual marketplace provides structured knowledge to different stakeholders with a pragmatic and well-grounded mid to long-term ambition of developing and consolidating a trusted expertise network, to be active and self-sustaining well beyond the project timeline.