Abstract A web-based intervention program for changing habitual energy-relevant behavior was tested at workplaces of Higher Education Institutions (HEIs). In a web portal an intervention package was provided, that had proven to be successful in past field studies. For analyzing the usability of this platform, the HEIs implemented the intervention program autonomously. The intervention was established at five HEIs (23 buildings). Intervention outcomes were operationalized by measuring the development of energy consumption. Considerable outcome differences were found between the participating HEIs. These might be based on implementation differences. To assess possible relationships between implementation and outcome differences, data regarding implementation issues had been collected by questionnaires and in workshops with HEI representatives. By tendency we found lower levels of implementation (i.e. reducing the intervention materials) and lower levels of participation to decrease the interventions' outcomes. Additionally, indications showed that cultural differences due to the HEIs location might have influenced implementation levels and the interventions' outcomes respectively.