Energy Investment Systems, Inc. | 112 followers on LinkedIn. When building owners contemplate a major improvement program, it is the time to consider all of the energy performance opportunities available. EIS works with each client building to consider the highest performing and most appropriate energy equipment available, to review the configuration of the building’s supply and generation of energy, and to integrate energy systems with user information technology. EIS works with top specialists and manufacturers in their various fields, from heating and cooling to electrical systems.