Researchers from UC Berkeley’s Center for the Built Environment and the University of Sydney studied the effect of industrial fans on heat load among factory workers at two facilities in Baton Rouge, Louisiana (United States). The study, titled “The Heat Tax,” ran across two three-week periods — late May/early June 2025 and August 2025 — with thirty participating factory workers. Periods with the industrial fans running were alternated with periods without ventilation, while researchers recorded environmental conditions, body measurements and worker-reported experience.
What the study found
Workers reported that the work environment with active fans felt approximately 5.6 degrees Celsius cooler (10 degrees Fahrenheit cooler in the source text). Seventy-nine percent of participants reported feeling more effective at their work when the air was moving, and all surveyed workers (100 percent) rated industrial fans as important to their workplace. Oral temperature and heart rate readings rose as ambient temperature increased, regardless of whether the fans were running. Sweat rate, however, was lower when the fans were on, both during the May–June mornings and in August.
Figures on productivity, energy and regulatory guidance
According to market analysis by manufacturer Big Ass Fans, which was involved in the study, fewer than 20 percent of US industrial facilities have conditioned air. Earlier research cited in the study shows that productivity drops by 1 to 2 percent per degree once indoor temperatures exceed 75 degrees Fahrenheit (about 23.9 degrees Celsius), and that work capacity can decline by 30 to 50 percent during peak heat. Industrial fan solutions are also said to use 20 to 30 times less energy than conventional air conditioning, while preserving the productivity gains. The study also points to differing guidance from health authorities: the US CDC advises using fans only below 90 degrees Fahrenheit (about 32.2 degrees Celsius), while recent WHO guidelines support fan use up to 104 degrees Fahrenheit (about 40 degrees Celsius). UC Berkeley researcher Charlie Huizenga noted that field studies in active production environments are rare “because they are difficult to carry out,” which he said underscores the practical value of this study.
Practical implications for the sector
This is relevant for EHS professionals because the study provides concrete evidence that relatively simple, energy-efficient measures such as industrial air circulation can have a measurable effect on both the physical strain and the perceived effectiveness of workers in hot production environments. Heat stress on the shop floor is a recognized occupational hazard that can lead to reduced concentration, fatigue and health complaints, and facilities that cannot or do not want to fully implement climate control may benefit from understanding alternative mitigation measures and the temperature limits within which they remain effective.
Source: The Heat Tax: Study Shows Industrial Airflow Offsets Extreme Heat Strain on Factory Floors, ISHN, 10 September 2026, https://www.ishn.com/articles/115590-the-heat-tax-study-shows-industrial-airflow-offsets-extreme-heat-strain-on-factory-floors
