Due to global climate change, the frequency, duration and intensity of heatwaves are on the rise, which is particularly dangerous for the elderly, poor and socially isolated, who often lack the financial means to own and operate traditional air conditioning units. Additionally, the increased use of air conditioning units causes increased rolling power outages due to greater power demands, causing further fatalities. While electric fans cost less and require much less power to operate compared to traditional air conditioning units, most public health agencies, including the World Health Organization, the UK’s National Health Service and the Centre for Disease Control in the United States, currently discourage the use of electric fans during heatwaves; despite a 2012 Cochrane Collaborative review which found no data in the literature supporting or refuting the use of fans during heatwaves. This paper explains how heatwaves affect individuals from a physiological perspective and explains the rationale for the current public guidelines. Furthermore, the paper presents physiological data (e.g. heart rate, core temperature, sweat losses, peripheral blood flow) collected from participants who were in a climate chamber which simulated the environmental conditions of several of the world’s most notable heatwaves including Paris 2003, Adelaide 2009, and Karachi 2015. This paper demonstrates that electric fans can be beneficial as a cooling strategy beyond the currently recommended conditions, and demonstrates how the effectiveness of electric fan changes over different combinations of ambient temperature and humidity levels.