The Scientific American reports on Environmental and Economic Pluses of the 4-Day Workweek

Local governments in particular have had their eyes on Utah over the last year; the state redefined the workday for more than 17,000 of its employees last August. For those workplaces, there’s no longer a need to turn on the lights, elevators or computers on Fridays—nor do janitors need to clean vacant buildings. Electric bills have dropped even further during the summer, thanks to less air-conditioning: Friday’s midday hours have been replaced by cooler mornings and evenings on Monday through Thursday. As of May, the state had saved $1.8 million.

No word on how this helps security, but clearly happier employees are less likely to become a risk (reduces motive). Although the time in the office is the same, I suspect the shift to longer days and fewer of them is also less risk (potentially reduces opportunity). Just as employees are on the road 20 percent less, they also potentially need authorization 20 percent less. The article does mention that health issues are reduced, surely because commuting and work-family pressures are reduced as well.

“Utah employees actually show decreased health complaints, less stress and fewer sick days,” Wadsworth says, noting previous research finding that fatigue is typically triggered by workdays over 12 hours. Early results from another multicity survey indicate that just 20 percent of respondents said they felt they ate more fast food and only 30 percent said they worked out less. In fact, 30 percent said they exercised more. Anecdotal evidence from Utah also points to an unexpected benefit: increased volunteerism.

That suggests four day work weeks are the limit. No need to get excited about trying the three day model. Another benefit might be more time at brick-and-mortar retail, which could boost the economy as well, and have more people outside for more days potentially reducing street crime.