The UK is currently experiencing a heatwave, prompting authorities to advise residents to check their smoke alarms. With temperatures soaring to a record minimum of 21.3°C, there is a heightened risk of electrical fires due to overheating appliances. Experts, including appliance repair specialist Ian Palmer-Smith and licensed electrician David Miloshev, caution against leaving fans running overnight, as this can lead to potential fire hazards and health issues. Continuous airflow from fans can circulate dust and pollen, aggravating allergies and asthma. Additionally, prolonged exposure to dry air can cause dehydration, sinus infections, and muscle aches. Sleep expert Martin Seeley emphasizes the importance of turning off fans at night to avoid these health risks. Staying hydrated is crucial, especially if the heat disrupts sleep, as even mild dehydration can exacerbate daytime fatigue. Residents are encouraged to prioritize safety by ensuring their smoke alarms are operational and to consider their health when using cooling appliances.