The drastic increase in energy prices is becoming a major concern in the plastics industry. Indeed, rubber and plastic manufacturing companies are recognizing the importance of focusing more on energy management to reduce the energy they use and, consequently, stay competitive in regional and global markets. Moreover, in the European panorama, the promotion of energy efficiency, use of renewable sources, and decarbonization are the key elements of the strategy that guides the common effort. Since the publication of the European Directive 2012/27/EU on Energy Efficiency, which established the obligation for large companies to undergo mandatory energy audits every four years, thousands of companies in Italy have performed an energy audit. Using a maturity model developed in collaboration with the Italian Energy, New Technology and Environment Agency, various Italian companies have been analyzed in reference to their energy management to assess the variation provoked by this obligation. From the results of the analysis conducted on a significant sample of companies from the rubber and plastics manufacturing sector, it emerged that on average the companies that have complied with the obligation of energy audit have increased their maturity in their energy management. The analysis was deepened by assessing the degree of coverage of the five maturity levels identified in the model: “Elementary”, “Occasional”, “Project-based”, “Management” and “Optimized”. Moreover, to identify the progress that occurred in the different aspects of Energy Management, the level of development of six different maturity dimensions has been studied: “Strategic approach”, “Awareness, knowledge and skills”, “Methodological approach”, “Organizational structure”, “Energy performance management and Information System”, and “Best practices”. Finally, the observed variations have also been statistically verified through the use of the paired t-test to make statistical inferences about the maturity of the overall population of the plastics industry.