Integrating (and evaluating) energy efficiency tactics into daily industrial practice is challenging. This paper addresses the experimental evaluation of energy efficiency tactics in industrial contexts. Based on different real-world scenarios, we assess five energy efficiency tactics for cloud-based software through individual experiments conducted across two companies. The results of the experiments show significant improvements in energy efficiency for three tactics, with two others showing enhanced efficiency albeit without statistical significance. In addition to the experiments, we draw lessons learned and practical insights into utilizing tactics in industrial contexts. Our results could guide practitioners in selecting and applying the most suitable tactic for their individual context. By linking tactics that emerged in the literature with evidence-based measures, we help including sustainability in software architecture design decision making.