Heat and productivity
A number of research studies have been undertaken on the effects on productivity of temperatures in the workplace.
We summarise them here:

• The performance of industrial work was worse at 24°C (75.2°F) than at 20°C (68°F). These precise conclusions were drawn by Pepler in experiments for the Industrial Fatigue Research Board and confirmed in a further study by Wyon for the New York Commission on Ventilation. Both experiments were carried for full 8-hour working days and over several weeks.
• A study by Vernon in a factory production line environment showed that heat stress has an adverse effect on the efficiency of men but a much smaller effect on women.
• In a further study by Wyon, office workers were exposed to temperatures of 68°F and 75°F for the same keyboard tasks and wearing the same clothing. The average performance of the group showed a reduction of up to 40 or 50%.
• The graph shows the results of reanalysed data by Wyon on office workers. Later in the day productivity reduces dramatically
• In an experiment by Pepler and Warner normally clothed young subjects performed mental tasks.They were most comfortable at 80.5°F but at this temperature they exerted the least amount of effort and subsequently produced the least work. They performed the most work at 68°F.
• Schweisheimer concluded that the average performance of workers dropped by 22% at an internal room temperature of 90°F.
• A paper written by Emerson L Besch for the American Society of Heating, Refrigeration and Air-conditioning Engineers acknowledged significant impairment in cognitive tasks (reception, arithmetic and recording of data)