A study suggests we should turn up the heat; it's not so simple.
TreeHugger Katherine recently wrote about a study, Battle for the thermostat: Gender and the effect of temperature on cognitive performance, which found that "at higher temperatures, women perform better on a math and verbal task while the reverse effect is observed for men." The study concluded:
In her conclusion, Katherine alluded to the issue of dressing for the season, noting that "if men ditched their heavy suit jackets and women opted for long-sleeve shirts over light dresses, perhaps the battle for the thermostat could even out a bit and everyone would feel more comfortable." I made a similar point earlier, in Big surprise: Women like warmer temperatures but men control the thermostat. But there are also other issues; on MNN I noted that "managers are setting it to the lowest temperature because you can easily put on a jacket to get warmer but you can only take so much off to get cooler and maintain decorum. It's hard to fix that."
Ultimately, our results potentially raise the stakes for the battle of the thermostat, suggesting that it is not just about comfort, but also about cognitive performance and productivity. Given the relative effect sizes, our results suggest that in gender-balanced workplaces, temperatures should be set significantly higher than current standards.
But I have more fundamental problems with this study.
The study was about the effects of temperature, and when you read the materials and methods section of the study, you find that the experiment took place in 24 sessions between the 25th of September to the 6th of December in an "experimental economics laboratory at Technical University of Berlin." The average outside temperature in Berlin during that time can vary from close to 20°C down to -2°, which will mean a dramatic change in what people are wearing. Meanwhile, the researchers are cranking the thermostat between 16.19 to 32.57°C and at no time do they tell us the correlation between the inside temperature and the outside temperature and what outdoor temperature the participants are dressing for. The researchers also don't tell us much about that experimental lab, whether it has windows, or what kind of mechanical system it has, only that they adjusted the temperature with "AC and electronic heaters."
The researchers say, "It is not just about comfort, but also about cognitive performance and productivity." But I would respond that performance and productivity is a function of comfort. And more importantly, that comfort is not a function of temperature, which is why information on the room and what people are wearing is so fundamental.
We are preoccupied with temperature because, technically, thermostats are easy, starting with a bi-metal strip that switches the furnace on and off. But comfort is much more complicated. As engineer Robert Bean explains, our bodies have about 166,000 thermal sensors and it is all about how they are feeling.
Whether we feel warm or cold depends on how fast our bodies are losing heat to the world around them. This depends on the air temperature in part; if the air next to our bodies, or on the outside of our clothing, is cold, then we lose heat to it more quickly than if it is warm.
So if those test participants dressed for a sunny September day and were placed in a cold lab, they are not going to be comfortable and they are not going to be very productive. And then there is the matter of the room and the windows; as engineer Es Tresidder notes:
We also lose heat through radiation, regardless of the air temperature, to the solid surfaces surrounding us. This radiative heat loss depends on the temperature of those surfaces and how close we are to them. The warmer they are the less heat we lose in this way; the colder they are the more heat we lose.
That's the issue of Mean Radiant Temperature, or MRT. It's the most important of what physicist Alison Bailes lists as one of the four factors that affect comfort, the others being temperature, humidity and air movement. Read his infamous post Naked people need building science for more graphic detail.
There's more, as Robert Bean lists here, including drafts, stratification, and metabolic rate. But the main point is that it is much more complicated than just temperature. For people to be comfortable and productive we need better buildings, better walls and better windows, with better air quality. We need better mechanical systems; you can't figure this out by simply throwing in a bunch of "electronic heaters." And we need better studies.
This, by the way, is the main reason I have become such a fan of Passivhaus or Passive House design; the walls and windows are almost the same temperature as the air they enclose, so you don't gain or lose heat from them very quickly. You are comfortable. And comfortable people are happy and productive people.
See also on MNN: Why do our offices feel like walk-in coolers?