The study “Low Efficacy of Periodical Thermal Shock for Long-Term Control of Legionella spp. in Hot Water System of Hotels” in which researchers from Biolinea Int. (J. Molina, M. Bennassar and S. Crespi) and the University of the Balearic Islands (J. Molina and E. Palacio) have participated. This is the first field study evaluating the impact of regular thermal shocks on the level of colonization by Legionella spp. in hotel hot water systems, a method recommended or required in different national and international guidelines and regulations, although in the absence of clear evidence in its favour. The results of this study suggest that regular heat shocks are not effective for long-term control of Legionella colonization of hotel hot water systems. These findings are of great interest to the hotel industry as eliminating unnecessary thermal shocks would save huge energy costs and CO2 emissions and avoid other potential side effects, including the risk of scalding. The article is available in Open Access https://www.mdpi.com/2076-0817/11/2/152