This study evaluates improvement in energy efficiency of an air conditioned building block employing energy conservation measures (ECMs) recommended by Indian Energy Conservation Building Code 2007 (ECBC) through a prescriptive route. First part evaluates energy savings by implementing five ECMs of envelope independently and two combinations of ECMs keeping constant thermostat setting throughout the year. In the second part of the study same ECMs are considered to the subject building model allowing thermostat settings as per thermal adaptation resulting from change in outdoor temperature. Actual measurements were taken and simulation model was fine-tuned. Annual energy consumption of building is used to evaluate the effect of individual ECMs and their combinations on both part of the study, i.e. fixed thermostat and adaptive thermostat settings. The simulation result shows that together with combination of all ECMs recommended by ECBC, small buildings can save up to 40% energy consumption as compared to buildings built with conventionally practised specifications of India. Effect of thermal adaptation itself offers up to 16% energy saving opportunity in small buildings considering adaptive thermostat settings. The potential of energy conservation through ECMs suggested by ECBC and adaptive set point gets significantly reduced for large size buildings having high internal heat gains. (C) 2012 Elsevier B.V. All rights reserved.