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Shivering in summer? Sweating in winter? Your building is living a lie

I have a challenge for the next time you’re at work. Take a look around at your colleagues. Now look at yourself. What are you wearing? It’s still winter (just), so if you’re in the southern states you…

Office temperature regulations are bad for comfort and the environment. Kim n Cris Knight

I have a challenge for the next time you’re at work. Take a look around at your colleagues. Now look at yourself. What are you wearing?

It’s still winter (just), so if you’re in the southern states you should be wearing a few layers. But my guess is neither you nor your colleagues are appropriately attired. In fact, if statistics are to be believed (and in this case it’s safe to trust them) you’re most likely wearing single layers in winter and jumpers in summer. It’s an odd phenomenon, even a little comical, but it has serious ramifications on your work and on our environment.

A combination of regulations and popular (but incorrect) misconceptions about building engineering has contributed to this problem. There is a widespread belief that the “optimal temperature” for human productivity is 21.5degC. But if you look at the science of indoor environmental quality (my speciality), there’s no basis for this belief .

This figure has been picked up and repeated so many times many businesses accept it as the truth, never questioning why so low or so specific. In fact, research demonstrates Australian air-conditioned offices perform better at 24-25 degrees in summer.

A too-cold office is bad for productivity and emissions. William J Sisti

While the difference might sound minor, the implications are significant. Indoor climate control (heating, ventilation and air-conditioning) accounts for at least half of the energy used in commercial buildings. Artificial lighting makes up a substantial slice of the remainder.

We now spend an average of 90% of our time indoors. The Intergovernmental Panel on Climate Change identified the global buildings sector as most promising for climate change mitigation, double the second most promising sector – agriculture.

In summer, the cooler you make your office the more energy it takes. Each degree of air conditioning saved equates to a 7-10% reduction in air conditioning costs. At the comfortable mark of 24 degrees, businesses could be saving up to 30% on air-conditioning use. Turning down heating in winter can have similar cost advantages.

Yet many of us shiver in summer and sweat in winter because this artificial figure, 21.5 degrees, has been enshrined in tenancy contracts. Craig Roussac, from one of Australia’s leading commercial building portfolio owners, Investa, says tenants have demanded buildings be air-conditioned to 21.5 degrees.

Meanwhile, companies leasing offices have written this temperature into tenancy contracts in the misguided belief it optimises comfort and productivity. Building owners and managers are unable to turn off or change air-conditioning settings to something more comfortable, productive and energy-efficient, because doing so risks legal repercussions.

“This sort of thinking is one of the reasons we are wasting so much energy,” says Roussac. “A better understanding of how we physiologically react to and perceive temperature can lead to significant savings in otherwise wasted energy.”

With sensible temperatures, you can dress for the weather. slworking2/flickr

Ironically, green building principles and green leases are also based on the so-called “science” that 21.5 degrees is an optimal figure. While it is admirable so many offices have adopted the green building principles of solar energy and indoor plants, at the same time they are ignoring savings from properly calibrating air conditioning systems and changing staff clothing habits.

I lead a team of researchers investigating building comfort at the University of Sydney. We’ve found that minor and inexpensive changes can have significant impacts on worker comfort. The science is compelling. We know adaptable spaces are much more important than ones where temperature is tightly controlled. Workers are more comfortable if they can control their immediate environments by drawing blinds and opening windows than when whole floors are uniformly cooled or warmed to an arbitrary figure.

We need to reduce energy use and then find ways of making what we do use go further. Tenants must stop demanding uniform cooling when negotiating leases, and property owners must explain how other changes, such as adaptable spaces, can contribute to productivity.

New technologies may well contain the key to overcoming the challenges posed by climate change, but until they’re developed and widespread we’re far better off moderating our demands. Given that we know air-conditioning and heating is so poorly calibrated in so many offices, it seems the perfect place to start.

So go on, put on a jumper and turn down the heating. You’ll be making your work, your office and your country better. It’s all just a matter of degree.

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30 Comments sorted by

  1. Dog Researcher

    PhD Student

    Wow, this is completely counter to my experience with buildings in Australia (I'm from the US, where I'm pretty sure the average office building is cooled to a balmy 20 degrees in summer!). My office building, on the older side, lacks insulation or double-glazing so it struggles to get above about 18 during the winter - and that's WITH the illicit space heater. During the summer we fare a bit better, since Melbourne summers are typically mild. I agree that an office with a temperature of 24 or 25 would be ideal, certainly that's the temperature at which I am most comfortable. I always assumed that the cold offices were because men often wear suits and get hot if it gets any warmer. Thanks for this article. Very informative.

    1. Tim Connors

      System Administrator / Public Serf

      In reply to Dog Researcher

      No, men get uncomfortable when the heating is turned up because there's about a 10 degree difference between men and women in comfort, as far as I can tell!

      My old workplace wasn't particularly chilly in summer -- about 25 when the air conditioning wasn't malfunctioning. I and the men were working in shorts and tee. In winter, the one sole woman wanted her little office heated to about 34 though, and wore freezer jackets otherwise.

      I really need a blanket and doona with a his and hers side.

  2. terry lockwood

    maths/media/music/drama teacher

    Where I work, I am in and out of aircon all the time. It is a rigmarole to get the target temp changed generally. It makes sense that in summer, while inside the clothes I have chosen for outside should be roughly right inside. In winter, I should not need to strip down to tolerate the aircon. The target temp should reflect the clothes people wear at that time of year.
    It all makes sense. It's logical.

  3. Clinton Roy

    Software Developer

    The other temperature craziness is public transport, trains and buses are often many degrees different to the outside temperature; I often carry a jumper or jacket during summer so I don't start sneezing.

  4. Paul Cm

    logged in via email

    Richard. Nice article, appreciate it!

    Couple of questions:

    1. A lazy observation of mine has seen a temperature tolerance differing between males and females. Can you comment further?

    2. I work on a new type of solar cell where the window can be used to as a means of photo-electric conversion, whereby bands of light are absorbed leaving others to transmit into say, an office space. The internal lighting therefore can be changed to various forms of coloured light -reds, greens, yellows, etc.

    Apart from 'sick building syndrome' literature - which is limited - I haven't been able to find too much on the effects of monochromatic variables. Any suggestions? No hurry by the way, just a side thought of mine.

    Thanks again for the article,

    1. Lorna Jarrett

      PhD, science educator and science advocate

      In reply to Paul Cm


      "temperature tolerance differing between males and females. Can you comment further?"

      As a female (I fit into a few other categories too BTW, most people do) I can't stand A/C, especially in summer - somehow simultaneously freezing and clammy. I'm more than happy to dress for the weather - what else is a wardrobe full of clothes for?

      The cruelest buildings (both psychologically and environmentally) are glass-walled ones chilled to shivering point - complete with a view of blue skies, frangipani blossom and pedestrians in summer clothes. Productivity goes out the window (well, out the front door anyway) as we head out on a coffee trip to warm up.

    2. Tim Connors

      System Administrator / Public Serf

      In reply to Lorna Jarrett

      But but but an architect got an award for that building! :P

  5. Mark Amey

    logged in via Facebook

    I agree with the entire thesis of this article. One of my observations, is that there are two seasons called spring and autumn, which are relatively mild, and allow humans, and other animals, to adjust to the extremes of summer and winter. I tend to dress the same all year (T-shirt and shorts when outside) because I allow my body to adjust. I'm often surprised at the amount of clothing that people wear, and wonder how they'd dress if it became really cold!

    1. Peter Elepfandt

      Medical Doctor

      In reply to Mark Amey

      Interesting point..
      I grew up in Germany and wondered why I recurrently felt so cold in winter walking to the bus at 10deg C in Brisbane. Until one day I figured that in Germany at 10 degC I never would have attempted to go outside with only a TShirt and Jumper.
      Obviously some people are able to adjust better than others....

      Peter the frog

  6. Rosemary Stanton

    Nutritionist & Visiting Fellow at UNSW Australia

    A major reason for my (admittedly fortunate) choice to work from a home office relates to air conditioning. I can't stand it and it's almost always too cold - designed for men in suits and ties, I suspect.

    It's not just workplaces though. When travelling, it's hard to find hotels with opening windows. I like cold weather (with appropriate clothing), but shopping centres and supermarkets are so chilly I grab what I need and hurry out. Cuts down on impulse buying!

  7. Bruce Moon



    Gotta agree on your observation that 24-25 is about right for summer; I've been doing that for a few years now.

    But, pray tell, is an appropriate aircon temp setting for winter?


    1. Bruce Moon


      In reply to Bruce Moon

      The last sentence should have been...

      But, pray tell, *what* is an appropriate aircon temp setting for winter?


      Cheers again

  8. Gerard Dean

    Managing Director

    Hey, am I missing something?

    My factory in Melbourne is fully insulated and air conditioned using split systems. Most of the load is heating during winter, not cooling during summer.

    On mild days we leave the roller doors open and don't turn on the system.

    If we set the temperature to 24-25 degrees in winter, we would pass out and the power bill would be enormous.

    What temperature do you recommend in winter?

    Gerard Dean

  9. Mary-Helen Ward

    logged in via LinkedIn

    An issue that we struggle with in our open plan office is that different people seem to sense the temperature differently. We have a few people who are always cold, even when the rest of us are comfortable - we keep our temperature at 22-23 all year round. They need to wear jackets, which makes it difficult for them to work comfortably. When we had an office with opening windows it was a nightmare - people were always opening them, while other people would close them! I don't think it's easy to get to grips with the reality reality of managing temperatures for 20 people in an open plan office.

    1. Peter Elepfandt

      Medical Doctor

      In reply to Mary-Helen Ward

      just speaks against the madness of having one large room with 20 people working on desks only separated by shoulder height room dividers (i.e. open plan offices)
      Can anyone tell me the advantage apart from cost saving (that is probably eaten up by decreased productivity due to being uncomfortable and exposed to constant noise)?

  10. bill parker

    editor wirter

    The generally accepted "comfort zone" temperature range is 18° - 28° C, but it will depend on humidity, It will also depend to some extend on where you where born and raised.

    I loathe offices in the summer - way too cold. But there is much more to this. Even the insulation value of chairs is critical!

  11. Peter Sommerville

    Scientist & Technologist

    For over 20 years I managed staff who for technical quality reasons were required to work in controlled atmosphere rooms, maintained at 20C and 65%RH. That is a constant temperature and humidity over the entire 12 months. When in the rooms in the summer they would dress as if it was winter. In the winter they would dress as if it was summer. Methinks the psychology of the external temperature experience dictated how they reacted to conditions in the rooms.

    1. Tim Connors

      System Administrator / Public Serf

      In reply to Peter Sommerville

      Psychology? Just simple acclimatisation. The first hot day of summer is not usually particularly hot, but gee, it feels hot. Similarly for stepping off a plane in Mildura mid summer if you're just come back from a ski holiday in the Alps. If you're acclimatised for summer, then of course going into a chilled 21degree room is going to be cold.

      Someone on the internet is the set of blogs from Antarctic researchers. There was one article there with mention of a heater thermostat that was adjusted…

      Read more
  12. Don Aitkin

    writer, speaker and teacher

    Interesting piece that raises more questions than it seems to answer. I like 22 degrees, and my car is set for that temperature. I no longer need to go to an office, other than that in my house, but I agree that in an office whatever the temperature is set at some will find it too cold and some not cold enough. And some always want to open windows and some don't. When I worked in the US in the middle of a Michigan winter the internal temperature was set at 75 degrees Fahrenheit, and people took off their overcoats and revealed shorts and short-sleeved shirts.

    But it is good that people are working on this problem, and I look forward to some useful suggestions.

  13. none at all


    Thanks for a very timely article and to the contributors who support it.
    Here on the Gold Coast, we didn't use either of our air conditioners last summer, although they were needed for two unusually warm afternoons the previous year. We use them frequently for heating on winter evenings, running at 26-28 degrees, depending on the humidity.
    Our main problem by day is that we wear shorts or light slacks and shirts for most of the year, but have to carry sweaters for supermarkets, professional offices, hospitals etc., which are usually several degrees below the ambient temperature and much drier than the conditions to which our bodies are attuned. My wife carries a list and races through the supermarket, to get back outside to warm up.
    All that is usually required during summer days is ventilation, or dehumidification.

  14. Alan John Hunter


    This is a prime example of the modern obsession with one size fits all, business and government seem obsessed with uniformity, especially when it denies logic, even when it is glaringly obvious that it can't or won't work.
    Another example, 50 kph speed zones, fine for crowded narrow inner city streets, however I live in a small country town with a big wide, long main street with footpaths and no pedestrians, nobody walks here, yet we have to crawl along at 50 kph when frequently, there might be if you are lucky one other car to wave at, also in industrial parks no kids, no houses yet 50 kph again?. I could go on for 100 pages with these sort of examples.
    Back to the temperature, we are quite comfortable living with 16/19 winter, and around 30 deg. in summer.
    I was unaware of the 21.5deg. requirement, and it seems to me to be about the dumbest thing I have heard of, a temperature that is only achieved in nature on a few fine days in spring and autumn.

    1. bill parker

      editor wirter

      In reply to Alan John Hunter

      My anecdote relates to a former Professor of architecture who had spent his career working on low energy buildings. After he retired I heard him give a summary history of his career and his parting remarks were along the lines of "we are not thermometers after all". Indeed. We respond to the immediate climate around us in many ways. Stick on the jumper indeed.

  15. Bruce Waddell

    logged in via LinkedIn

    This is a discussion that has been delayed too long. I'm just pleased that this topic is raised before summer. Why people want to freeze (my word) inside buildings during the summer is beyond my understanding. The mechanical services in many buildings make it difficult for tenants to adjust temperatures but a change to a wider range is, as this article suggests, long overdue.

    1. bill parker

      editor wirter

      In reply to Bruce Waddell

      I suspect the answer lies in the way mechanical engineers are paid. Big AC plant, bigger fee?

  16. Morten Erichsen (b.arts)

    Available For Hire (conditions apply).

    I find this article a little amusing, culturally speaking.
    Having grown up in northern Europe, I was just a child, when the 21 degree decree was made as an energy saving measure for the northern countries, whose energy consumption always concerned itself with heating. People preferred about 23-24 degrees in their living rooms funnily enough.
    It was passed off as gospell back then to ram home quick change around the first oil crisis.
    That's where the 21 degree 'law' comes from. You just have to produce better propaganda for the southern hemisphere instead of importing copy wholesale. You do indeed have the same aims.

  17. John Harland

    bicycle technician

    Our house is comfortable at 16 - 17 degrees in Winter. Even after removing coat scarf and hat, you will probably be wearing more clothing than in Summer so it makes nonsense to have the house as warm as at that time of year.

    Having the house too cool in Summer knocks you about when you have to go outside. It is also difficult when coming back inside because the over-cooled air is moving too little to cool you down, so you swelter far more than if the air were warmer, but moving.

  18. Bruce Munday

    communications consultant

    Could it be that the C price might prompt people/businesses to at last consider this self evident approach to economic issue? That the environment might also benefit would be an unusual conjunction of good outcomes.
    Aircon in cars is another area where many people seem unaware that energy (and hence fuel) is used to run the system.

    1. Peter Elepfandt

      Medical Doctor

      In reply to Bruce Munday

      brown coal fired power plant? I don't care, I get my electricity out of the wall socket.....