Why building designers need to provide agency to inhabitants and acknowledge that some external stress is acceptable.

Marcel Schweiker (RWTH Aachen University) and Richard de Dear (University of Sydney) discuss the neutrality fallacy and resilience. They explain why indoor environments do not need to be stress free in order to support their occupants’ resilience.

Humanity is currently bedevilled by multiple wicked problems. Global climate change is proceeding apace. Science is being denied and medical progress wilfully wound back. Facts are replaced with “alternative facts.” Populations of the developed economies are ageing. Mental health crises are picking up speed, artificial intelligence is displacing the real stuff, et cetera, et cetera, ad nauseum.

The Canadian prime minister Mark Carney’s words at the World Economic Form in January 2026 seem equally relevant to buildings as they are to global finance, geopolitics, health, energy, and environment: “We are in the midst of a rupture not a transition.“. Long-held assumptions and heuristics are being displaced by uncertainty, and the buildings sector is not immune. Many “facts” and predictive tools needed for design and operation of buildings have been rendered ineffectual in the face of uncertainty.

As a result, resilience has become the new buzzword in the building professions’ lexicon, gently nudging aside previous favourites like sustainability and green buildings. What is the definition of resilience? It is not synonymous with robustness which refers to the maintenance of the status quo in the face of external perturbations, but rather as an approach supporting flexibility to appreciate and gain strength through changes. As Friedrich Nietzsche wrote in 1888: “What doesn't kill you makes you stronger“.  

What has resilience got to do with the human-building-system?

Resilience emerged in the discipline of materials science circa 1858, entered social sciences in the 1950s initially in relation to psychopathological problems of children, and was adopted by ecological sciences in the 1970s (Schweiker 2022). Definitions of resilience are as varied as the disciplines in which it has been applied. For the concept of resilience in the context of human-building systems, we propose the following definitions:

The ability of a system to respond effectively to internal and external disruptions (stressors) and to bounce back, or ideally, bounce forward, in order to fulfil its needs.

and

Human-building resilience results from the synergy between the resilience of buildings and building services on the one hand, and human resilience on the other.

These definitions require further exploration of some basic concepts of human stress management. This can then inform the requirements for building design and operation to increase human-building resilience.

First, we need to understand how buildings and their occupants react to external stressors. We’ll illustrate with one of the wicked problems, namely extreme heat waves attributed to global climate change (Ebi et al. 2021) and their impacts on public health. Building characteristics such as window-to-wall-ratio, solar heat gain coefficients, thermal insulation, fixed or operable windows, amount of thermal mass and external shading, HVAC-systems and other types of climatisation (Aviv et al. 2025), all affect the thermal gradient between indoor and outdoor climates. Application of climatic design principles alongside appropriately sized HVAC equipment and the requisite energy can deliver buildings in which indoor thermal conditions are entirely disconnected from the vicissitudes in the climatic conditions outside the building. Such buildings might be labelled “robust” because of the relief they provide occupants through constantly neutral indoor climates, free from thermal stressors.

Does the delivery of static indoor environments actually support human resilience?

Human reactions to thermal stressors are at least as complex as those of buildings. Depending on intensity of the stressor and personal characteristics of the individual, various physiological and behavioural thermal regulatory responses can be observed. Initial reactions are typically changes to peripheral blood flow volumes, vasodilation or vasoconstriction in hot or cold exposures respectively, then sweating or shivering in response to more extreme stressors. At the behavioural level, responses range from minor changes in clothing insulation all the way up to adjustments to heating or cooling equipment.  

Before overcoming the stressor, the individual undergoes a certain level of strain. Stress is the objectively measurable external quantity, while strain represents the subjectively perceived quantity, based on the stress-strain model found in occupational health psychology (ISO 2017). Magnitude of strain differs from person to person, the stress-strain model from occupational psychology also highlights that consequences of a strain can be impairing or facilitating. It is typically taken for granted that impairing the consequences of strain such as illnesses need to be avoided by all means,. However in the context of indoor climates, this avoidance response is generalised to even minor thermal stressors. Most research activity and regulatory standards around the design and operation of buildings aim for the complete avoidance of all stressors. For example, one of the most pervasive models found in national and international standards on indoor environmental quality is an index called PPD - Predicted Percentage Dissatisfied (ISO 2025; ASHRAE 2020). Any subjective thermal sensation falling outside the slightly-cool-to-slightly-warm range is deemed unacceptable according to the PPD index. The standards under discussion here are applied in both design and operational contexts, and their stated intent is the minimisation of the PPD index. This focus on avoiding all impairing effects of thermal strain overlooks potential short- or long-term facilitating effects. Moreover, the ultimate effect on the buildings sector has been described as neutrality fallacy (DeKay & Brager 2023).

A companion model to the stress-strain model in our discussion is the “transactional model of stress and coping” by Lazarus & Folkman (1984), in which the evaluation of a stressor is considered as a two-step process. The initial appraisal of a stressor sorts it into one of three categories - positive, dangerous or irrelevant. Which category is chosen depends, among other things, on the individual’s past experiences with the stressor in question. If a stressor is categorised as dangerous on the basis of past experience, then a secondary appraisal is made of the available resources required to cope with it. If resources are deemed to be sufficient, the stressor is directly counteracted. However, if resources are insufficient, then the stressor can evoke elevated strain. This second step depends essentially on the individual’s expectations of their capacity to handle the situation without ill effect.

What evidence exists for these stress-strain concepts and the association between experiences, expectations and the neutrality fallacy?

The logical inference from the preceding discussion is that building occupants with limited experience of stressors, even mild ones, are likely to appraise any excursion outside the region of neutral thermal sensation as dangerous and beyond their capacity to cope. As a result, the range of acceptable temperatures in such buildings has been shown by countless empirical studies in the adaptive comfort literature to be much more constrained compared to that found in buildings with dynamic indoor climates, such as those with natural ventilation or passive heating and cooling systems in operation (de Dear & Brager 1998; Parkinson et al.2020). Recent studies substantiate the connection between expectations and thermal comfort; when expectations were not met, thermal comfort decreased and more positive expectations were associated with higher levels of thermal comfort (Rissetto et al. 2022).

The stress-strain model along with the transactional model of stress-and-coping provide a connection to two previously distinct thermal comfort literatures: adaptive comfort and personal environmental comfort systems (PECS). The building occupant who has agency over their comfort (e.g. access to PECS can be assumed to have greater perceived control) is  less likely to feel threatened by moderate variations of indoor temperature compared to the occupant with negligible perceived control. Countless adaptive comfort field studies report the same observation: that occupants with access to thermal coping mechanisms (e.g. operable windows, ceiling or personal fans, localised heating appliances) demonstrate greater tolerance of indoor temperature variations than do occupants of tightly regulated buildings operating under the neutrality paradigm (Földváry Ličina et al. 2018). The nexus between perceived control and thermal tolerance has become the raison d'être of PECS, because they permit facility managers to relax HVAC control deadbands, and therefore reduce overall energy demand significantly without adversely impacting occupant thermal acceptability (Hoyt et al. 2015).

In summary, the lens of stress-strain and transactional coping raises several new questions about the relationship between indoor environments and their occupants. The underlying perceptual mechanisms and their connection to occupants’ past experiences and expectations seems to tie together several strands of contemporary thermal comfort literature into a coherent whole.

What are the implications for building design and operation?

The present approach to building design and operation needs to shift from the delivery of a specific singular benchmark value towards more holistic approaches of human resilience. Two components of the salutogenic model for health promotion (Antonovsky 1996), i.e. comprehensibility and manageability, provide a pathway between the mechanistic approach and empirical findings with the future agenda.

First, the context of a building should be comprehensible to the occupants. Building design and operational strategies that do not aim to extinguish the diurnal, synoptic, and seasonal-scale rhythms in the external environment of a building will afford their occupants a greater variety of indoor environmental conditions; valuable experiences extending beyond thermal neutrality with stimulating effects. At the same time, they will be more readily comprehensible for the users based on their daily experiences and less likely categorized as potentially dangerous.

Second, building design and operation should be targeted to increase the manageability of environmental stimuli for the occupants. Providing efficient and responsive controls such as PECS or operable windows, enables occupants to experience their ability to control their environmental stimuli; individuals will gain an understanding how the building, its systems and their body reacts to various conditions. In parallel to such experience, expectations will rise that also future similar fluctuations can be dealt with without having to rely on energy-intense conditioning systems. When deviations of environmental stimuli from neutrality occur that are still considered as potentially dangerous, the second appraisal will be more likely resulting in a sense of having sufficient resources available to deal with them.

This reorientation of the occupant-building relationship towards comprehensibility and manageability is a prerequisite for buildings intending to enhance human resilience. The neutrality fallacy in building design and operation has had the opposite effect on the resilience of occupants, rendering them hypersensitive to even the most trivial fluctuations in the elements of indoor climate due to a lack of comprehensibility and manageability. This will also help in case of extreme conditions or failures of supporting active systems to reduce additional mental strain by categorizing the stressor as either irrelevant or potentially dangerous but manageable (i.e. having sufficient resources to deal with it).

In conclusion, people are not exact thermometers, but all are calibrated differently, depending on our prior exposure and the thermal history shaping our expectations. Building professionals must acknowledge the neutrality fallacy and how it extinguishes human thermal resilience precisely at a time in history when we need to become more resilient with less resources. This includes a shift from the mere consideration of relief, towards considerations of human needs such as comprehensibility and manageability. Knowledge from the cognate disciplines around building science (e.g. environmental psychology, occupational or environmental medicine and planetary health) need to be incorporated into built environment professionals’ curricula, particularly civil and mechanical engineering, and especially architecture. Research needs to understand which individuals and stimuli, elicit facilitating and manageable or impairing strains to support human resilience beyond relief and towards encouragement and enjoyment.

“Heaven is the place, a place where nothing, nothing ever happens.”
(David Byrne & Jerry Harrison - Talking Heads 1979)

References

Antonovsky, Aaron. (1996). The salutogenic model as a theory to guide health promotion 1. Health Promotion International, 11(1): 11-18. https://doi.org/10.1093/heapro/11.1.11  

ASHRAE. (2020). Standard 55-2020, Thermal environmental conditions for human occupancy. American Society of Heating, Refrigerating and Air-Conditioning Engineering, Atlanta, USA.

Aviv, D., Rysanek, A., Ma, N. & Vakalis, D. (2025). Cooling People, Not Spaces: Surmounting the Risks of Air-Conditioning Over-Reliance.Kleinman Center for Energy Policy. https://kleinmanenergy.upenn.edu/research/publications/cooling-people-not-spaces-surmounting-the-risks-of-air-conditioning-over-reliance/

de Dear, Richard J. & Brager, Gail Schiller. (1998). Developing an adaptive model of thermal comfort and preference. ASHRAE Transactions, 104(1): 145-167. https://escholarship.org/uc/item/4qq2p9c6

DeKay, Mark & Brager, Gail. (2023). Experiential Design Schemas. San Rafael: Oro Editions.

Ebi, Kristie L., Capon, A., Berry, P., Broderick, C., de Dear, R., Havenith, G. …  Jay., O. (2021). Hot weather and heat extremes: health risks. The Lancet, 398(10301): 698-708. https://doi.org/10.1016/S0140-6736(21)01208-3

Földváry Ličina, V., Cheung, T., Zhang, H., de Dear, R., Parkinson, T., Arens, A., … Zhou, X. (2018). Development of the ASHRAE Global Thermal Comfort Database II. Building and Environment, 142: 502-512. https://doi.org/10.1016/j.buildenv.2018.06.022  

Hoyt, T., Arens, E. & Zhang, H. (2015). Extending air temperature setpoints: Simulated energy savings and design considerations for new and retrofit buildings. Building and Environment, 88: 89-96. https://doi.org/10.1016/j.buildenv.2014.09.010

ISO. (2017). ISO 10075-1:2017 Ergonomic principles related to mental workload Part 1: General issues and concepts, terms and definitions. International Organization for Standardization, Geneva.

ISO. (2025). ISO 7730:2025 Ergonomics of the thermal environment — Analytical determination and interpretation of thermal comfort using calculation of the PMV and PPD indices and local thermal comfort criteria. International Organization for Standardization, Geneva.

Lazarus, R. S. & Folkman, S. (1984). Stress, appraisal, and coping. New York: Springer.

Parkinson, T., de Dear, R. & Brager, G. (2020). Nudging the adaptive thermal comfort model. Energy and Buildings, 206: 109559. https://doi.org/https://doi.org/10.1016/j.enbuild.2019.109559.

Rissetto, R., Rambow, R. & Schweiker, M. (2022). Assessing comfort in the workplace: A unified theory of behavioral and thermal expectations. Building and Environment, 216: 109015. https://doi.org/https://doi.org/10.1016/j.buildenv.2022.109015  

Schweiker, M. (2022). Rethinking resilient thermal comfort within the context of human-building resilience. In Routledge Handbook of Resilient Thermal Comfort, edited by J. Fergus Nicol, Sue Roaf and Hom B. Rijal. Routledge.