The current research study, aims to couple the indoor environmental quality (IEQ) in countryside schools with energy efficiency. A detailed investigation took place on three different types of rural schools (old, new, and renovated) conveniently located for comparison purposes within a radius of 2.5 km from each other. The IEQ assessment covered the period autumn 2013-spring 2014 and included both long term measurements and spot recordings. In terms of indoor air quality all three buildings performed poorly, registering average CO2 concentrations in excess of 2000-3000 ppm and even approaching the health hazard level of 5000 ppm. Based on these concentrations, the corresponding ventilation rates have been calculated at 2.4 L/s/person (renovated school), 2.25 L/s/person (new school) and 0.7 L/s/person (old school). The IEQ index was calculated using the experimental data allowing the three analyzed schools to be better rated. The new and renovated buildings rank class Con the IEQ index scale and class A from an energy consumption standpoint, whereas the old building is rated D class (IEQ) and C class (energy efficiency). This shows that high energy consumption, as is the case for the old school, does not necessarily result in better comfort conditions despite their inverse correlation. (C) 2015 Elsevier B.V. All rights reserved.