The City of Berlin in partnership with Berlin Energy Agency (BEA) has done pioneer work to develop and apply an excellent model to improve energy efficiency in buildings. The model called “Berlin Energy Saving Partnership” (ESP) offers efficient refurbishment of public and private buildings with the pivotal advantage to release building owner of any investment costs. Due to releasing building owners from expenses and delivering savings immediately, ESPs are very successful. An accredited Energy Service Company (ESCO), which is to be determined through tendering, finances and implements appropriate energy saving investments to achieve pre-defined energy and cost reductions. In their bids, ESCO’s put together their investments targeted at delivering specified energy savings and respective CO2-reductions.