The achievement of energy efficiency in the building sub-sector is considered a very important issue in contemporary research and development efforts by engineers, architects and environmentalists. This is because of its direct impact on national economies and indirectly on the environment and the general well being of future generations. This paper attempts an evaluation of the potentials of passive design in the warm humid zone of Nigeria by assessing the level of energy conservation in building through solar orientation. Model experimental buildings were constructed and comfort factors (indoor and out door temperature, relative humidity, solar radiation, etc) measured, and the climatic and technical (construction) factors determined for each of the model buildings using known methods. Regression model on the effect of solar radiation on the climatic and technical factors reflecting the amount of heat energy required to achieve an acceptable comfort level for each building was formulated. Results from the study show that there is strong evidence of tremendous potentials in passive design as ecotechique for energy conservation in buildings.