Today’s buildings are becoming more technologically complex, which has given us an even better possibility to monitor the buildings in-use performance. This paper studies what key performance indicators real estate developers choose to monitor as well as how they go about to collect the necessary data. In addition, it is also discussed how the information from the monitor systems are integrated in the day-to-day maintenance of the building. The paper has a case study approach, in which two commercial developments, with high ambitions regarding the environmental profile, have been chosen.