For half a century, building performance has relied on comfort indices such as Predicted Mean Vote and Predicted Percentage Dissatisfied. They are elegant: put in air temperature, radiant temperature, humidity, air speed, clothing and activity, and they return a prediction of how comfortable people will feel. Buildings around the world are designed and certified on that basis.
Yet comfort is not a property of the air. It is a perception, produced by the brain from signals that also shape emotion, attention and behaviour. Two people in the same room at the same temperature can feel very differently, and the same person can feel differently on different days. The indices treat that variation as noise; neuroscience suggests it is the signal.
Our review in Architectural Science Review distinguishes indoor thermal comfort, the physical condition, from perceived thermal comfort, the experience. It examines how six regions of the brain respond to thermal variation, and critically analyses the limits of PMV and PPD in capturing what occupants actually feel. The evidence comes from neuroimaging and physiological studies that read the body’s responses directly rather than asking people to rate a scale.
We propose a framework for bringing neuroscientific evidence into comfort assessment. The aim is not to replace engineering models but to complete them, so that thermal comfort is understood as a cognitive and emotional phenomenon central to wellbeing and performance rather than a narrow band on a psychrometric chart.
The practical stakes are considerable. Overheated or overcooled buildings waste energy and reduce productivity, and fixed set points ignore the people who are least comfortable. Design that takes perception seriously can do better on both counts.
The work behind it
Azzazy, S., Ghaffarianhoseini, AH., GhaffarianHoseini, A., Naismith, N., and Omrany, H. (2025). The brain response to indoor thermal comfort: From the thermal perception to the current indoor thermal comfort indices. Architectural Science Review, 68(4), 241 to 262.
The review continues the neuroarchitecture research he began with the Architectural Engineering Lab in 2019, which used EEG and fMRI to read how buildings affect the people inside them.