Richard de Dear and the Problem With 22 Degrees

De Dear is Professor Emeritus of Building Science at the University of Sydney and Director of its Indoor Environmental Quality Laboratory. His research is the most cited in the field globally: 42,600 citations, an h-index that places him in Stanford’s top two percent of researchers across all disciplines. It helped write the international standards that now govern how buildings are designed and operated. He was appointed Member of the Order of Australia in 2020, and last year received the Pettenkofer Gold Medal, the highest honour in indoor environmental science. In my opinion, he has earned the right to question the orthodoxy.

What makes his work so significant is not simply that it changed technical standards. It challenged the assumptions beneath them.

“The human species is the most adaptable species on the planet.”

Simple sentence. Radical implication. Because if humans are inherently adaptable, the entire logic of the standardised, mechanically stabilised indoor climate begins to look surprisingly fragile.

And perhaps that is the deeper problem with 22 degrees. Not the number itself. But the mindset behind it.

When comfort became standardised

When de Dear began his PhD at the University of Queensland in 1981, thermal comfort research was dominated by a single prevailing theory: that there was one universally ideal indoor condition, a narrow combination of temperature, humidity and air speed that most people, anywhere in the world, would find comfortable. 22 degrees in Sydney. 22 degrees in Singapore. 22 degrees in Stockholm.

Against this sat a competing theory, known as adaptive comfort, developed by researchers Michael Humphreys and Fergus Nicol in the 1970s. Their proposition was more intuitive and far more human-centred: people adapt. To climate. To seasons. To what they have recently been exposed to. Comfort is not fixed; it shifts with context.

De Dear found the adaptive model compelling because it aligned with lived experience. He describes arriving in Singapore from Denmark in the 1980s and feeling initially overwhelmed by the tropical climate.

“I thought, I’m not going to last. This is a hostile climate.”

Within months, he had acclimatised. I can speak to that personally. Having lived for extended periods in Italy, then Minnesota, and now South Australia, I have experienced that same arc: the initial shock, the gradual recalibration, the body progressively adapting to a new normal. This is not willpower. It is physiology.

That experience became foundational to de Dear’s career. “We don’t need 22 degrees in Singapore,” he told me. “That’s crazy. It’s crazy from a scientific point of view because it’s disarming our adaptive capabilities.”

The adaptive comfort model eventually became highly influential internationally, particularly after de Dear collaborated with ASHRAE – the American Society of Heating, Refrigerating and Air-Conditioning Engineers – on research that later shaped global thermal comfort standards. But despite decades of evidence, much of the built environment still operates according to assumptions developed during an era of cheap energy and mechanical certainty.

Most people already sense this. Almost everyone has felt the strange contradiction of being cold inside a building supposedly conditioned for comfort. Overcooled offices. Boardrooms requiring jackets in summer. Spaces that are technically performing to specification while somehow feeling thermally lifeless. The problem, de Dear argues, is not poor calibration. It is the assumption that comfort itself can be universally standardised.

How architecture learned to ignore climate

One of the most striking moments in our conversation came when de Dear described the historical impact of air conditioning on architecture.

“The advent of air conditioning liberated architects from the constraints of climate.”

It is an extraordinary statement because it explains so much about the modern built environment. Mechanical conditioning allowed buildings to detach from environmental responsiveness in ways previously impossible. Orientation, shading, thermal mass, ventilation and climate-sensitive envelopes became less essential once large HVAC systems could simply override external conditions. Glass towers proliferated. Sealed buildings became normal. Thermal stability became synonymous with comfort.

The industry became extraordinarily sophisticated at controlling indoor temperature. At the same time, it arguably became less sophisticated at understanding human comfort.

“We build against climate instead of building with climate.” That sentence reaches far beyond sustainability rhetoric. It challenges the philosophical direction of modern building design itself. Once architecture became dependent on mechanical systems to erase climatic variation, buildings no longer needed to negotiate intelligently with their environment. Cheap fossil-fuel energy allowed the industry to compensate technologically for decisions that climate-responsive design would previously have prevented.

Today, many of those assumptions are colliding with reality. Rising energy costs. Heatwaves. Grid instability. The conversation around comfort is no longer just about convenience. It is becoming inseparable from resilience.

The body does not experience warmth numerically

For architects and builders especially, one of the most important insights de Dear offers is also the most counterintuitive: thermal comfort is not simply about air temperature.

The body exchanges heat continuously with surrounding surfaces through both convection and radiation. Walls, floors, ceilings and glazing all participate in that exchange. This means a room can technically reach 22 degrees while still feeling cold if surrounding surfaces remain significantly cooler than the body.

“You’re receiving radiation from the walls, from the window, from the floor, from the ceiling.”

That observation reopens an older and often overlooked conversation about how humans actually experience warmth not simply as heated air, but as a relationship with surfaces, radiation, enclosure and spatial conditions. De Dear explained that heated floors, for instance, do not simply warm air; they exchange radiant heat directly with occupants while naturally warming the air in the lower occupied zone. The physics is straightforward. The implications for design are significant.

Modern HVAC culture has largely conditioned the industry to think about comfort numerically: air temperature in, thermal comfort out. But humans do not inhabit buildings as thermostats. They experience warmth through surfaces, through asymmetry, through the subtle sensory relationship between the body and the environment surrounding it. This may explain why some spaces feel comfortable despite lower ambient temperatures, while others feel strangely cold despite technically meeting specification.

There is also the matter of who “comfort” is being designed for. De Dear’s research has shown that thermal preferences vary substantially with gender, age, metabolism, clothing, acclimatisation and hormonal change. Women, on average, prefer warmer indoor temperatures than men. Older occupants often do too. Yet office temperature settings have historically skewed toward male clothing conventions in ways that remain surprisingly embedded in workplace culture. “These set points,” de Dear observed, “are more or less decided to bias males in workplaces over females.” The so-called “average occupant” it turns out, is fictitious.

His response is not to abandon shared environments but to rethink them. Rather than pursuing a single fixed condition intended to satisfy everyone equally, buildings need to provide more flexibility, more occupant agency and more localised control. Thermal comfort, in this framing, stops being purely an engineering conversation and becomes a human-centred one.

Australia’s particular blind spot

De Dear was candid about the local context. “Australian buildings evolved in an era of incredibly cheap, undervalued energy.” That observation explains much of the country’s thermal performance legacy: poor insulation, minimal double glazing, heavy dependence on mechanical systems. Europeans arriving in Australia are often shocked by the thermal quality of local housing, particularly given the country’s increasingly extreme climate conditions.

Australia has one of the world’s highest rates of residential air-conditioning adoption. The technology exists. The thinking behind it has been slower to evolve. “The industry is incredibly conservative,” de Dear noted, and that conservatism matters because buildings are long-lived. The assumptions embedded in projects today may persist for fifty or even one hundred years.

Many of the assumptions underpinning current comfort culture were developed during a very different energy era – before climate resilience became central, before electrification, before widespread concern about peak demand or energy security. For architects and builders, this creates an increasingly important challenge: not simply how to add larger systems, but how to think differently about what comfort actually is.

Beyond 22 degrees

Near the end of our conversation, de Dear said something that stayed with me. “Buildings hang around for decades.” The structures being designed today will operate within future climates that may look profoundly different from those shaped by assumptions of the past – not simply warmer, but more extreme, more volatile, more energy constrained.

What makes de Dear’s work so important is not simply that it challenged existing standards. It challenged the worldview behind them: the assumption that humans experience buildings uniformly; that tighter mechanical control automatically produces better comfort; that architecture became less dependent on climate once air conditioning arrived; that comfort can be reduced to a number.

The problem with 22 degrees is ultimately not about temperature. It is about the way modern buildings learned to prioritise thermal control over thermal understanding. De Dear’s work suggests the future of comfort does not lie in controlling buildings more aggressively. It lies in designing buildings that work more intelligently with climate, with surfaces, with energy, and with the adaptive capabilities humans already possess.

“We have to build with climate instead of building against it.”

That sentence took forty years of research to earn. It deserves to be taken seriously.