Why office air conditioning thermal standards fail women

If you think your female colleagues are making a fuss for no reason once the air conditioning is switched on, think again: office thermal standards simply are not designed with women in mind. They were set more than 50 years ago by men, for men, and have never been properly updated since.

When summer rolls back around (especially this week, which has been truly awful), air conditioning is turned back on in many workplaces. Although French labour law does not require employers to fit air conditioning as a matter of course, it is clearly more pleasant to work in a mild atmosphere with recirculated air. Even so, that “comfort” is relative: for a large share of women employees, the return of the air con signals the start of a long season spent fighting temperatures that are too cold-temperatures their male colleagues usually find perfectly bearable.

That widely shared experience is exactly what a team of researchers from California and Australia set out to demonstrate, with figures to back it up. In a study published on 8 December 2021 in Scientific Reports, they show that workplace temperatures are simply not suitable for women.

Although the research was conducted in the United States, employees in France are in much the same position: the thermal rules applied in their offices follow the same international standards, built around PMV (Predicted Mean Vote) and later incorporated into ISO 7730, which applies across European countries. These standards are now badly out of date and suffer from a design bias that the scientific community had already flagged in the early 2000s-yet standard-setting bodies have not acted to bring them up to date. It feels particularly anachronistic at a time when some companies proudly publicise their “inclusivity charters”, equality labels, CSR commitments and other progressive reforms.

Women in the office: victims of air-conditioning sexism?

How the researchers gathered the evidence

To reach this conclusion, the researchers combined two separate, independent datasets. The first consisted of nearly 39,000 responses from a survey of occupants in 435 office buildings spread across 168 US cities. The second source was more informal and unusual: 16,791 tweets posted between 2010 and 2019 by employees complaining about feeling cold at work.

What the results show about thermal discomfort

The first key finding was that 38% of respondents said they were unhappy with the temperature in their workplace-almost double the 20% threshold set by current thermal comfort standards. Among those dissatisfied, women accounted for close to two thirds. The likelihood of experiencing thermal discomfort was 1.8 times higher for women than for their male colleagues.

PMV and ISO 7730: standards built around a male reference body

The standards in question were developed in the 1960s, as mentioned earlier, using the PMV model. This mathematical index was formalised by the Danish engineer Povl Ole Fanger, who calculated it from what was treated as a “reference” human body-though in reality it was not truly representative: a sedentary man wearing a suit and tie. The heat output from his body (58.15 W/m²) was treated as a universal human value, even though women’s resting metabolism is 20 to 35% lower than that.

In practical terms, women naturally generate less heat and therefore need a warmer ambient temperature to stay in thermal balance. Yet this physiological gap was never incorporated into the PMV model, even though that framework is still used worldwide today.

The authors also pointed to another influence, more cultural and social in nature: in office settings, men generally wear more layers of clothing than women. However, the researchers qualified this explanation, arguing that-based on the available data-summer clothing differences between men and women are not pronounced enough, on their own, to account for the thermal comfort gap measured in the study.

Air conditioning: a small thing that costs a lot

Productivity, set points and the price of over-air-conditioning

This disparity has a major effect on productivity, because the researchers found a strong correlation between perceived temperature and performance. Across the cohort as a whole, 42% of women said the temperature harmed their ability to work, compared with 27% of men.

The 15-point gap is linked by the authors directly to the prevalence of over-air-conditioning, not to “women being especially sensitive to cold”. They also argue that the explanations commonly repeated in scientific literature (lower metabolism or lighter clothing) “have a perverse effect”. In their view, they frame “women as the source of the problem, rather than the thermal environments of offices themselves”. The issue is far from unsolvable, they add, because it would be enough to “raise office temperatures in summer, in line with thermal comfort standards”. This is “within reach of any company” and would “be enough to correct the gender bias linked to set point temperatures [editor’s note: the target temperature programmed on the thermostat]”, while also helping organisations cut their electricity bills and, to a smaller extent, reduce their contribution to global warming.