Sustainable business development is a challenge that requires both organizational change and changes to individual behavior. We report on the design and implementation of an app-based decision support system designed to promote environmentally responsible behavior among individuals in a B2B setting. The app, known as the "Green Fingerprint" was designed in collaboration with a commercial real estate firm and subsequently deployed in several tenant sites in the greater Stockholm area. We measured energy productivity defined as revenue in Swedish Kronor/kilowatt hours of electricity consumption. Over a two year period participating firms were able to significantly increase energy productivity by as much as much as 100% as a result of direct feedback and adopting conservation techniques recommended by the system. Increased energy productivity resulted in annual energy costs that were substantially less than if energy productivity had not increased.