Beyond COVID-19: How the manufacturing industry should prepare

Lighting On The Factory Floor


Improving Work Environment




16 factories, 15000+ garment workers


Department for International Development, UK Government, University of Michigan, Yale University, Private Enterprise Development in Low-Income Countries (PEDL), Shahi Exports








All else equal, productivity is lower on hotter days. Garment factories rarely control temperature on the production floor. Thus, to a large extent, outdoor temperatures determine the environment workers experience inside the factory.


What incentive can we give businesses to make the physical work environment more comfortable for workers?


We partnered with Shahi Exports, India’s largest apparel export house, to test the impact of replacing fluorescent lights with LED lights in 26 of their factories. Over the last decade, buyers have become more stringent about environmental regulations on the factory floor. This led to a staggered roll-out of LEDs across factories within Shahi based on who the respective buyer was. This generated a seemingly random replacement which took the form of substituting a portion of compact fluorescent lights targeted at individual operations with an equivalent number of small LED lights mounted on individual workers’ machines. On average, each factory replaced about 1,000 fluorescent lights consuming 7W each, with LED lights consuming 1W each.


We tracked administrative data on productivity, efficiency, and other workplace outcomes for all workers and found:

  1. Replacing fluorescent lights with LEDs reduces energy consumption by roughly 85%, reducing the average indoor temperature by 2.4°C.
  2. LED installation has a large impact on hotter days, when heat stress reduces worker productivity the most; there is almost no impact of LEDs on cooler days. This is because the relationship between temperature and productivity is not linear. In the absence of LED lights, efficiency appears to be a decreasing function of temperature, with the largest declines in efficiency occurring at the highest temperatures. The presence of LED lights reduces indoor temperature, combatting a part of the productivity decline at high temperatures.

Finally, we performed cost-benefit calculations for LED adoption, looking at efficiency gains and the firm's costing of the entire shift. If only energy savings are taken into account, it would take more than three and a half years to break even. However, when the productivity benefits are also considered, the firm breaks even in less than a year after LED installation. The average factory in our data gains about $2800 in power consumption savings, and about $7500 in productivity.

Scale up

In hot climates, LED lighting, compared to fluorescent lighting, is much more affordable than a naïve comparison of energy cost savings would suggest. All new Shahi factories now use LED lighting.

Image credits: Nayantara Parikh

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