Pay As You Save® (PAYS®) is a registered trademark in the United States of Energy Efficiency Institute (EEI). Co-Principals Harlan Lachman and Paul A. Cillo created the PAYS system between 1998-1999. The trademark applies within the U.S. Aspects of EEI’s PAYS system have been applied by Energy Efficiency Services Ltd. (EESL) in India, to finance energy efficiency upgrades including LED lightbulbs, street lights, fans, and water and sewage pumps.