22⁰C is neither natural, nor inevitable. But it is hugely important: around half the energy used in buildings is used to keep them at something like this temperature, all over the world and whatever the weather outside. So how come 22⁰C?
Ole Fanger’s thermal comfort equation (1970) has a lot to answer for. Fanger, a Danish engineer, developed a method for working out how much heating and cooling would be required to keep people 'comfortable'. Amongst other things, this meant making assumptions about what people wear. Fanger invented a new unit, the 'Clo', especially for the purpose. The Clo represents the insulation value of clothing and the scale is set such a man’s light weight business suit equals one Clo.
Standard room temperatures suppose standard clothing – and by default buildings are therefore designed for people wearing suits. Many other standards follow: for example electronic technologies are often designed to work best at 22⁰. Such devices are prone to fail if they overheat, and in the UK this is especially important in justifying the spread of air conditioning where none existed before.
As more and more buildings are designed to provide 22⁰ C, this becomes the norm. It becomes what people expect and when that happens, anything other than 22⁰C. begins to seem uncomfortable.
From an environmental point of view, and on a global scale, the massive energy demand that follows is unsustainable. Much less energy would be needed if room temperatures swung with the seasons and if people adjusted their clothing – and their daily routines – to suit.
To take Fanger’s equation for granted, and to continue producing buildings and energy systems capable of delivering ‘comfort’ as we know it today is to lock societies into high levels of energy demand. So is there any alternative?
Can we imagine a future in which the waistcoat and the string vest are again normal office wear? Or in which children are sewn into their clothes for the winter, as used to be the case? And in hot climates, not change dress codes rather than cooling to counter the effect of wearing a suit and tie? These are not entirely fanciful questions.
In 2005, the Japanese government refused to heat or cool public buildings between 20 and 28⁰C. The Cool Biz programme, as it was called, was a success – reducing energy consumption and changing styles and conventions of office wear on a societal scale.
Understanding how indoor climates come to be as they are and recognising that meanings of comfort are in any case always changing is an important first step in working towards a lower energy future. As the Cool Biz initiative demonstrates, room temperature can be re-defined and, looking ahead, there is no reason to suppose that standards which are normal now will remain so forever.
In exploring these issues the interactive exhibition, 'Heating, cooling, lighting: what is energy for?' provides fascinating insight into some of the stories that lie behind everyday energy use and into the energy and environmental policy challenges that lie ahead.
Professor Elizabeth Shove teaches on our MA Sociology programme.
- 'Heating, cooling, lighting: what is energy for?' can be seen at the Campus in the City, St Nicholas’ Arcades, 8 Ashton Walk, Lancaster - 12-6pm.