Energy efficiency (EE) Improvement is one of the most important targets to be achieved on every society as a whole and in buildings in particular Energy Smart Building aims to accelerate the uptake of EE healthy buildings that by integrating smart technology and solutions consume radically little resources while enhancing the quality of life This paper addresses how uninterruptible power supply (UPS) particularly when configured in distributed DC mode can become an Energy Efficient (EE) solution in high tech buildings especially when integrated with complimentary Power Quality (PQ) measures The paper is based upon PQ audits conducted at different IT-intensive modern building Some of the mayor objectives of the PQ studies were detecting the main involved disturbances by PQ monitoring identifying the power disturbances root causes characterizing the electromagnetic compatibility level of equipments and installation and providing guidelines for Implementing energy-efficiency solutions It was found that the main problems for the equipment installed were harmonics and voltage sag (dip) Finally this paper demonstrates the impacts of generalized electronic devices on the PQ of the buildings and the implications on energy uses (C) 2010 Elsevier B V All rights reserved