Thermal comfort standards were based on a single man.

Every week the research group I’m part of discusses a paper from the literature. It’s a effective way of keeping up to date with new work in the field. I might get into a regular habit of writing up some thoughts from these discussions here, but whether or not this happens, I thought I would talk here about last week’s paper, “Energy consumption in buildings and female thermal demand“.

The field of building engineering spends a good deal of effort establishing standards for the effective operation of buildings. These cover a wide range of properties of a building, from comfort to sound levels. For thermal comfort, the UK follows a range of BS and EN standards – here’s a pretty comprehensive list. Thinking about these standards, and what they mean for energy demand in buildings, is an important part of the struggle to decarbonise the economy;¬†around 30% of our energy use happens in buildings.

In the USA, ASHRAE standards do a similar job, but staggeringly the ASHRAE standard for indoor environments was determined using data from a single 70kg 40 year-old man. The paper focuses on gender differences in thermal preferences, and finds that there are differences between the sample they used and the standard which was based on one person – young adult females prefer a warmer office environment. Generally, there are a very large number of variables that are thought to determine thermal preferences.

Initially, I had assumed that if this finding was generally true that overall heat demand should be higher, if we were to satisfy everyone’s thermal comfort. But, as Clare pointed out in the discussion we had, while that might be true of cold countries like the UK, for countries where thermal energy demand relates to cooling decreasing the overall cooling energy used in office buildings might make the overall population happier. This is potentially good news for reducing climate change – the population as a whole might be happier if we used air conditioning less. Although, it probably wouldn’t be that simple.

Reading this paper was a reminder too that designing buildings that keep people happy is extremely difficult. There is a terrifying nexus of considerations that must go into this process. While a standard based on a single man is clearly deeply deficient, questions remain about the tension between general standards and the preferences of actual building users. Negotiating these tensions whilst minimising energy use is problem of a wholly greater order of complexity.