This paper intends to examine the key drivers of household environmental attitudes and energy-saving behavior using both observed and stated attitudinal factors. Beginning with an assessment of energy-saving behaviors Item Response Theory (IRT), we associate hierarchical multivariate regression with an innovative variable selection approach via Elastic Net Selection (ENS). Our empirical study is based on data from the 2012 ENERGIHAB project survey. Empirical evidence in this article contributes with new insights about the main explanatory factors of household energy-saving behavior. The main results further suggest that energy-saving behavior tends to fluctuate throughout time in households. Our findings and approach generate broader methodological insights into energy efficiency analysis through behavioral aspects.