Why is it so cold in here? Setting the office thermostat right – for both sexes

4 Aug

https://theconversation.com/why-is-it-so-cold-in-here-setting-the-office-thermostat-right-for-both-sexes-45585?utm_medium=email&utm_campaign=Latest+fr

August 4, 2015 6.07am AEST
Authors

Shane Maloney
Professor and Head of School, Anatomy Physiology and Human Biology at University of Western Australia

Andrea Fuller
Professor, School of Physiology; Director, Brain Function Research Group at University of the Witwatersrand

Duncan Mitchell
Honorary Professorial Research Fellow at the University of the Witwatersrand, Johannesburg; Adjunct Professor in the School of Anatomy, Physiology and Human Biology at University of Western Australia

Disclosure statement

Shane Maloney receives funding from The Australian Research Council and Meat and Livestock Australia. He is affiliated with The National Tertiary Education Union as a member of the UWA branch committee.
Andrea Fuller receives funding from grants from the National Research Foundation, South Africa.
Duncan Mitchell receives funding from the South African Medical Research Council, the South African National Research Foundation, the Australian Research Council and Oppenheimer Memorial Trust, for research related to thermal physiology in non-human mammals and to pain pathophysiology. The South African Medical Research Council funded some research in pain pathophysiology (another research interest of his) as well as research related to thermal physiology in non-human animals. He is Director of Partners in Research (a South African independent pharmaceutical market research company).
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The University of Western Australia provide funding as a founding partner of The Conversation AU.

The University of the Witwatersrand

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Keeping office workers from feeling too hot or too cold is no simple task. Kjetil Kolbjornsrud/Shutterstock
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If you work in an office, chances are you or the person sitting next to you has grumbled about it being too hot or cold. No one likes rugging up on a summer’s day to contend with the air-conditioning. Or having to shed one too many layers in winter to compensate for stifling heat indoors.

According to a paper published today in the journal Nature Climate Change, this scenario is more likely if you’re a woman. Climate control systems in office buildings are often set according to an old formula based on men’s thermal comfort. This gender bias, the authors argue, is wasting energy.

What is thermal comfort?

Keeping office workers from feeling too hot or too cold is no simple task. While most office air conditioners control only air temperature, the way we exchange heat with the environment depends on a suite of environmental factors. And so does our thermal comfort.

Engineers need to consider:

the humidity
the movement of air (wind speed)
the radiation temperature (the temperature of everything the body can “see”)
the temperature of everything we touch.
In the 1970s, Danish engineer Ole Fanger developed a model to determine the combination of environmental variables that we find comfortable.

Because heat exchange also depends on individual factors such as body size (and therefore body surface area), metabolic rate (that determines metabolic heat production), tissue insulation (related to the amount of body fat), and clothing, Fanger’s own experiments showed that no office thermal environment ever would satisfy everyone.

Even before Fanger, we knew that, at the low wind speeds typical of offices, radiant heat exchange mattered more than convective heat exchange. In other words, radiation temperature is more important for thermal comfort than air temperature. You could argue that offices should have wall conditioners, rather than air conditioners.

In today’s Nature Climate Change paper, Dutch researchers Boris Kingma and Wouter van Marken Lichtenbelt show that if the thermostat is set for men, as it usually is, the air temperature will be too low for women.

Because women are smaller, the authors explain, they generate less metabolic heat than men, and so will not feel comfortable in winter at office temperatures set for men.

By the same logic, if the thermostat is set for Europeans, it will be too low for Asians, who weigh, on average, 30% less than Europeans.

In countries such as Australia and South Africa, where air conditioning generally is used for cooling, setting the thermostat to satisfy large people in summer will leave smaller people feeling too cold.

But while Fanger’s equations predict thermal comfort – how satisfied we are with the thermal environment – that is only one of the body functions relevant to the question of where we set the thermostat.

More than just comfort

Heat exchange also affects our body temperature control (how hot our bodies are), thermal sensation (how hot or cold we feel the environment to be), and our performance (how well we do on a particular task).

Those body functions are not necessarily correlated. In a hot bath, for instance, body temperature rises and we feel hot, but we meet Fanger’s criterion for thermal comfort: we wouldn’t want the temperature to be any different.

We perform some cognitive and physical tasks best when we’re slightly-uncomfortably cold. But manual dexterity is better at a warm 32°C than at 20°C in simulated factory work.

Performance at some tasks drops off when body temperature rises, even if we do not feel the environment as warm. For that reason, and those outlined in the Nature Climate Change paper, children probably underperform on learning tasks in classrooms that teachers assess as feeling just right. Perhaps the smaller children should set the thermostat.

As if all that complexity weren’t enough, Australian researchers have challenged Fanger’s 1970s thermal comfort model on the basis of the concept of adaptive thermal comfort. Should we set the thermostat at the same level in winter, they asked, when we are acclimated to colder outdoor environments, as in summer?

Some occupants of offices in the tropics want the thermostat set higher than Fanger predicts. Thirty years ago, people of European ancestry living in Darwin rejected air conditioning in the “the Dry” (July and August) because they felt overcooled. Though it’s unclear whether modern Darwinians, many of whom use air-conditioning at home, would say the same.

So, what can we do?

We certainly could maintain thermal comfort and simultaneously relax the demands on the thermostat if we were prepared to wear warmer clothes in our offices in winter and cooler clothes in summer. Selecting clothing also would solve the dilemma of providing thermal comfort to both men and women in the same office.

In the new Nature Climate Change paper, the authors estimate that energy consumption of residences and offices “adds up to about 30% of total carbon dioxide emissions”.

It’s true, we could substantially reduce the energy required for acceptable thermal environments in offices and consequently reduce greenhouse gases. But that approach would require us to abandon the compulsion to create a shirt-sleeve thermal environment in offices, and to vary the thermostat between summer and winter.

We would also need to switch to wall-conditioning rather than air-conditioning and use green engineering to get the thermal design of the office building right. We can be comfortable without it costing the earth.

Environmental health
Heat
Office
Thermoregulation
Heating
Cooling

8 Responses to “Why is it so cold in here? Setting the office thermostat right – for both sexes”

  1. Debra August 4, 2015 at 3:00 pm #

    Who takes control of the thermostat in our office is a weekly battle! I can tell you that I’m always freezing…year-round. I am also certain there isn’t one thing about the air conditioning system that is eco-friendly. I grew up without air conditioning and a very minimal heating system. I don’t think I’ll ever be happy with unrelenting air conditioning. I really freeze!! Thanks for this, Uta. Very interesting.

    • auntyuta August 4, 2015 at 6:04 pm #

      You’re freezing year-round, Debra? Gee, this is horrible!
      With an air-conditioned office I am sure I’d have similar problems that you have. Well, I am glad I never had to work in an air-conditioned office. Where I worked in the 1950s we had central heating. In winter our boss had the temperature set at 18 Degrees Celsius. He advised us to dress warmly. As a young person I was able to cope with such a low temperature for office work. These days I find 18 Degrees not warm enough. At the computer or watching TV I have an electric heater next to me. I like the room warmed up to at least 20 Degrees. Peter and I we both do not like air-conditioning and have none in our house. When I visit friends, who have air-conditioning. I always try to dress extra warmly. Still, I usually end up freezing, while everybody else feels not one bit too cold.

  2. stuartbramhall August 5, 2015 at 1:16 pm #

    Here in New Zealand, most work places are still uninsulated. The only way to stay warm in winter is to wear thermal underwear, heavy sweaters, scarves and in some cases fingerless gloves.

    • auntyuta August 6, 2015 at 9:43 am #

      In the big cities of Australia most work places, shopping centres and trains and buses are air-conditioned. Some of the older air-conditioned trains have the air blowing everywhere. After sitting on the train for a while, the air feels much too cold. I always have to protect my ears with hats and scarves. In winter I wear sweaters and jackets.
      In summer, when I am dressed lightly because of outside heat, the air-conditioning on the train or bus may feel great for about half an hour. Once the body has cooled sufficiently, the air-conditioning may feel much too cold. All our trains have fixed windows these days, most city hotels too. I hate it when I cannot open the windows!

  3. gerard oosterman August 5, 2015 at 11:17 pm #

    I have found that in the English speaking world, the feeling of discomfort is somehow seen as good for the spirit and soul. Heating, even in England is at best tolerated and many still feel it corrupts and invites sinful thoughts.
    An Englishman is happiest eating cold cabbage standing up in a draught.
    My mother never felt so much cold as when they lived in Australia.
    We have two good gas heaters and have the temperature at 20c. Also installed double glazing and despite the roof being insulated, spent money on insulating all the ceilings both downstairs and upstairs.
    In Finland people live warmer than in the average house here in Australia.

    • auntyuta August 6, 2015 at 9:56 am #

      I like it that on planes and buses I can usually turn the ventilator off when it is blowing too strongly! 🙂
      Germans seem to be the opposite of the English. Every apartment, every office, every shopping centre is centrally heated for most of the year.
      The average house here in Australia is built like a summer cottage. In Germany a cottage like this might be used for summer only. In the cooler months Germans like to stay in a very well insulated and thoroughly heated apartment.

      • gerard oosterman August 6, 2015 at 11:48 am #

        I often thought in Holland it was over the top. People heat at 26c. The trains were so hot but when I dared to open a window it was; Mijnheer, mijnheer, wat doet U tog.? Het tocht.
        Sir, sir..what are you doing now? It is now so draughty.

      • auntyuta August 6, 2015 at 12:29 pm #

        When visiting Berlin during an extremely cold winter, we could not believe how overheated big department stores were. We felt extremely uncomfortable walking for any length of time in an overheated building like this while wearing our winter-coats.

        As I child I was told not to leave a door open which could cause a draught. A complaint would go like this: Mach die Tür zu, es zieht ja hier wie Hechtsuppe! When forgetting to close a window, the saying was: Mach das Fenster zu. Wir heizen doch nicht die Strasse!
        (We do not want to heat the street!)

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