Physiological adaptation to heat¶
How quickly people adapt to outdoor conditions, why a running mean beats a monthly average, and what has to be measured.
People adapt to their local environment in the short term, by adjusting their behaviour and clothing to the outdoor environment they’ve experienced recently. Some adaptive comfort models reflect this by taking the average mean temperatures in the past month as an indicator of predicted comfort temperatures, like the ASHRAE model. However, studies have shown that after only 7 days human adaption to changes in outdoor temperatures is significantly reduced (see Figure # below). Instead, the running mean is a more accurate indicator. The running mean temperature is an average of the temperatures in the last week; however, the model puts more emphasis on more recent days than earlier days. This is because you are more likely to be impacted by the temperatures from yesterday than 6 days ago. This is in line with the European standard method set out in Standard EN 15251.
Where localised survey information is available which uses both methods, the running mean figures should be used in preference. The ARC Cool Buildings toolkits provided will build in this preference. The tools will only require the user to input the hourly outdoor temperatures, and the internal temperatures that were recorded. To demonstrate building performance using the comfort model it is therefore necessary to have access to measurements of both the internal and outdoor humidities and temperatures inside and outside of your building. Ideally, internal and external temperature measurements should be recorded on an hourly basis via data loggers placed in permanently shaded spots. The external data logger outside the building, should also be both well shaded and also protected from rain.
Where this measured data is not available data from other sources, as local as possible could be used – for example publicly available airport weather data or from other publicly managed weather stations. An airport is likely of course have a different temperature profile than the building and surroundings, because airports are typically located in open landscapes and may or may not be impacted by the urban heat island effect.
Figure 3 [Cite source]
Open questions on this page
These are unresolved in the source document - the author's own queries, and the figures and citations still to be filled in. They are repeated here rather than resolved, because a threshold shown as settled when it is still under discussion would be misleading.
- However, studies have shown that after only 7 days human adaption to changes in outdoor temperatures is significantly reduced (see Figure # below)
- [Cite source]
Confirm any of these with ARC before relying on them for a project.
Source: ARC Technical Criteria - 205
Reference · confidence medium · Imported 2026-09-12, not yet reviewed · next review 2026-12-12
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Citation key: physiological-adaptation