The customary usage of HVAC systems by modern offices could be diminishing productivity amongst office-bound workers by reducing indoor temperatures to levels below the optimum range for human cognitive function.

Alan Hedge, director of the Human Factors and Ergonomics Laboratory at Cornell University contends that human beings are designed to best function within limited range of optimum temperatures given the fact that we're warm-blooded mammals.

According to Hedge, however, most office buildings use HVAC systems to bring indoor temperatures well below the desired level for human comfort or productivity.

Research conducted by Hedge and his colleagues attests to a significant decline in worker productivity when office temperatures are excessively low.

A 2010 study led by Hedge that was published by the journal HVAC&R Research used the computer activity and number of errant keystrokes of office workers to assess their productivity.

The study found that when temperatures remained in the low 20's the output of workers diminished significantly, while the rate of typing errors conversely increased.

As temperatures fall beneath the mid-20 degree celsius mark human output undergoes a corresponding linear decline, and a difference of just several degree celsius can have a huge impact on productivity levels as assessed by the number of keystrokes entered by workers on their computers.

Workers in offices at a comparatively cool 21 degrees Celsius would type at half the speed of those in a workplace at 25 degrees Celsius, which is considered to be close to the optimum temperature for human productivity.

After the high 20's human productivity drops off again, with increased heat levels having the general effect of making people feel sluggish or lethargic.

Hedge imputes the reduced productivity of workers in coolers offices to the efforts they make to keep warmer, which can include rubbing their hands together or pottering around the workplace. These physical actions can reduce productivity by distracting people from their work and impeding their focus.

While Hedge's research may have established the optimum temperature range for human action, the actual temperatures of most office buildings tend to remain just beneath this level, which means businesses could be suffering from productivity hits.

Ever since the 1960's offices have tended to keep their temperatures between 20 to 23 degrees Celsius, due to the assumption that workers would be suit-wearing males.

Changes in the workplace - such as the loosening of sartorial expectations as well as the entry into the workforce of women whose thermal responses can differ from those of men, mean that modern businesses may need to dial up the temperature of their HVAC systems just slightly if they hope to raise productivity.


  • Marc, I find such issues interesting in the sense that more often than not building HVAC set up does not follow the logic of various inputs and considerations. This productivity perspective aligns with a common sense 'middle-range' satisfaction aimed at comfort for a maximum number of people. Outside conditions should be factored for both system functionality and likely clothing worn outside the building. The first acknowledges the basics of heat pump temperature differentiation and efficiency and the second considers the impact of entering and exiting the building. If productivity fits within a range of say 23 to 25 degrees I'd be setting the temperature to 23 in winter and 25 in summer to cover all factors. What tends to hamper HVAC effectiveness is when the reverse logic is used to over compensate for outside conditions.

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