New research published in the journal Environmental and Resource Economics concludes that hot weather reduces worker productivity even if their work places are air conditioned.

The study, led by the UK’s University of Exeter, focused on outdoor temperatures and worker productivity at a high-tech factory in China.

It found that, despite climate-controlled conditions inside the factory, productivity dropped on average, by 0.83% for every 1°C increase in outdoor temperature.

Furthermore, the research team found that night-time heat (which can affect sleep) caused some of the decline in productivity.

But daytime heat was found affect productivity even after cool nights.

It is not clear why this happens, but the researchers say their findings are a “cautionary tale” as governments and businesses adapt to rising global temperatures.

We usually think about climate change in terms of its impacts on a huge scale, but it also affects individuals.

Previous research has shown that - unsurprisingly - hot conditions reduce productivity when people work outdoors, or in buildings without air conditioning.

These new findings, which show that heat affects workers even in a climate-controlled factory, provide further evidence of the potential economic impacts of climate change.

Policymakers and business leaders might assume that technology such as climate-controlled buildings can mitigate the effects of climate change.

However, in this study, climate control on its own was not sufficient to insulate a firm from the effects of high outdoor temperatures. 

The study used data on the daily maximum “wet bulb” temperature - a measure that takes account of both heat and humidity.

And they combined this with individual-level data on the quantity and quality of work done in 35,190 worker-shifts (involving 635 separate workers).

The factory in the study makes silicon wafers for solar panels.

The delicate nature of the wafers means that, to ensure quality, all workshops have climate-control systems that keep them at a constant temperature of 25°C (or 77F) with a relative humidity of 60%.

The 0.83% productivity dip for each 1°C of temperature rise meant a worker produced 22.6 to 33.4 fewer wafers daily.

Notably, the study also found that a wet-bulb temperature over 28°C was associated with 5.8% lower productivity compared to a typical day.