An analogy might be drawn with the use of light quality as a design element, truly a venerable old architectural tradition. The light quality—direct, indirect, natural, artificial, diffuse, dappled, focused—can be subtly manipulated in the design of a space in order to achieve the desired effect.

Thermal qualities might also be included in the architect's initial conception and could influence all phases of design. Instead, thermal conditions are commonly standardized with the use of modern mechanical systems that can be specified, installed, and left to function independently of the overall design concept.

Indeed, environmental control systems tend to be treated rather like the Cinderella of architecture; given only the plainest clothes to wear, they are relegated to a back room to do the drudgery that maintains the elegant life-style of the other sisters: light, form, structure, and so forth.

The hearth, a refuge of dry warmth from a cold world, and the oasis, a preserve of coolness and moisture in a desert wilderness.

One way not to be there (without dying).

"Yes, we have felt happy and alive together."

The Finnish word loyly, meaning "the steam which rises from the stones" originally signified spirit, or even life.

The tradition of the great shade tree.

The Anasazi Indians of the southwestern United States were remarkably clever in choosing the sites for their cliff dwellings. They invariably chose locations shaded in the summer by an overhanging ledge of the cliff, but exposed to full sun all winter long. With their backs to the cliff, the dwellings were protected from the winter winds and also took advantage of the thermal mass of the earth to moderate the temperature flux.

Many peoples of North Africa migrate within their buildings in both daily and seasonal patterns to take advantage of the various microclimates the buildings create.

Fascination with this potential for control of our environment has prompted the invention of mechanical systems that have made natural thermal strategies seem obsolete by comparison.

There is an underlying assumption that the best thermal environment never needs to be noticed, and that once an objectively "comfortable" thermal environment has been provided, all of our thermal needs will have been met. The use of all of our extremely sophisticated environmental control systems is directed to this one end—to produce standard comfort zone conditions.

People have a sense of warmth and coolness, a thermal sense like sight or smell, although it is not normally counted in the traditional list of our five senses.

As with all our other senses, there seems to be a simple pleasure that comes from just using it, letting it provide us with bits of information about the world around, using it to explore and learn, or just to notice.

There is a basic difference, however, between our thermal sense and all of our other senses. When our thermal sensors tell us an object is cold, that object is already making us colder. If, on the other hand, I look at a red object it won't make me grow redder, nor will touching a bump object make me bumpy.

We should note that all of these places of thermal extremes (Finnish saunas, Japanese hot baths, American beaches and mountains) have their opposites close at hand. There are possibly two reasons for having the extremes right next to each other.

The first is physiological: the availability of extremes ensures that we can move from one to the other to maintain a thermal balance.

The second might be termed aesthetic: the experience of each extreme is made more acute by contrast to the other.

Such clues from other senses can become so strongly associated with a sense of coolness or warmth that they can occasionally substitute for the thermal experience itself. For example, the taste of mint seems refreshing and cool regardless of what temperature it is. Similarly, the pressure of heavy blankets conveys a feeling of warmth quite independent of their actual thermal qualities.

Perhaps the human fascination with fire stems from the totality of its sensory stimulation. The fire gives a flickering and glowing light, ever moving, ever changing. It crackles and hisses and fills the room with the smells of smoke and wood and perhaps even food. It penetrates us with its warmth. Every sense is stimulated and all of their associated modes of perception, such as memory and an awareness of time, are also brought into play, focused on the one experience of the fire. Together they create such an intense feeling of reality, of the "here and nowness" of the moment, that the fire becomes completely captivating.

We need an object for our affections, something identifiable on which to focus attention. But in a typical office building, to what can we attribute the all-pervasive comfort of 70ºF, 50% relative humidity? Most likely, we would simply take it all for granted. When thermal comfort is a constant condition, constant in both space and time, it becomes so abstract that it loses its potential to focus attention.

The louvers automatically open to let solar radiation in when the sun shines and close in the evening to prevent radiant heat loss, controlled and driven by the shifting weight of freon.

We look into the greenhouse and watch the Skylids closing automatically, one by one and in no particular order, and we are aware of the hot air rising, cold air settling. They remind us that the earth is turning and the day is ending.

Thermal information is not differentiated in our memory; rather it is retained as a quality, or underlying tone, associated with the whole experience of the place. It contributes to our sense of the particular personality, or spirit, that we identify with that place. In remembering the spirit of a place, we can anticipate that if we return, we will have the same sense of comfort or relaxation as before.

The inglenook, the gazebo, and the porch swing also have strong definitions of their spaces. They are each a bit like a little house set off for a special thermal purpose. They might be termed "thermal aediculae". Although the term aedicula is most often used in conjunction with a sacred or ceremonial little house, it can also be used to describe any diminutive structure used to mark a place as special.

Summerson contends that there is a basic human "fascination of the minitature shelter." Perhaps this is because the aedicula intensifies ones experience of the place by working someone like a caricature. By reducing some things in scale, it exaggerates the importance of other things, most especially the size of a person in relation to the space.

In America our tendency has been to get away from thermal conditions as a determinant of behavior. Instead, we have used our technology to keep entire living and working complexes at a uniformly comfortable temperature. As a result, our spatial habits have become diffused, and activities that were once localized by thermal conditions have spread out over a whole house or building. We forget, unless a system breaks down, that such wide-ranging use of space is extremely dependent upon the available heating and cooling equipment.

Sharing the experience of a pleasant thermal setting may add an extra bonus to courtship. The gentle and cooling breeze of the southern porch swing provided a happy excuse for a couple to sit quietly together. A more technological version might be seen in the type of car that the teenagers of the 1950s considered ideal for a hot date—the convertible. Slightly more erotic, perhaps, were the atrium and green houses that were favorite settings for romance in Victorian England. The lovers could get lost among the leaves of the exotic tropical plants and possibly mistake the hot, humid atmosphere for their own concealed passion.

The Japanese have notoriously unheatable houses. They have traditionally preferred to design their houses to be cool and airy in summer and then to get by in the winter with localized ways to heat the body. Smallest of all means is the kairo, a little case carried around in pockets or between layers of clothes that contains a warm charcoal ember.

The association of comfort with people and place are reinforced by the ritualized use of a place. Using a place at a set time and in a specific manner creates a constancy as dependable as the place itself. It establishes, in time and behavior, a definition of place as strong as any architectural spatial definition, such as an aedicula, might be. Ritualized use can do more than reinforce the affection for a place. Through ritual, a place becomes an essential element in the customs of a people.

We are not now inclined to regard modern heating and cooling systems as representative of a spiritual realm. The physical principles involved in their operation are thoroughly understood; there is no mystery about them. They are simply functional, designed according to straightforward engineering practice to serve their intended function as efficiently and conveniently as possible.

And yet functionalism itself can be a kind of religion.

...From the fifties and sixties we have inherited numerous heating and cooling systems created within an ethos of universal convenience. Machines to maintain our thermal comfort were conceived of as mechanical servants, providing for our every need while, like an English butler, remaining as unobtrusive as possible.

Karen Terry's house in Sante Fe, designed by architect David Wright, is perhaps one of the most compelling passive designs.

Stepping down its hillside site in four tiers, it nestles low into the ground. Thick adobe sidewalls create a strong sense of shelter and its banks of windows look resolutely to the sun. The image is very much of a house attuned to sun and earth.

Rather than providing the convenience of a constant indoor temperature regulated by a thermostat, a passively solar-heated house may go through an air temperature flux as great as 20ºF per day. People learn to live with this flux.

Living in a solar house is a whole new awareness, another dimension. I have the comfort of a house with the serenity of being outdoors—protected, yet tuned in.

The Indian stone temple also included, in its architectural form, the means for being blessed by the four elements—earth, wind, water, fire.

• Before entering the temple gates, one removed one's shoes to touch and be blessed by the earth.
• Then upon passing through the temple gateway, one is blessed by the air with a gust of wind.
• A blessing by water is obtained by bathing in the temple tank, or at least descending its steps to touch the water.
• Finally, on entering the cool interior of the sanctuary, the worshipper is given a mark on the forehead with ashes taken from a sacred flame by an attendant priest. Even this blessing by fire has a slight cooling sensation to it.

Perhaps it is only coincidental that each of these four blessings is associated with a cooling sensation; and yet, the use of forms and materials that inevitably create coolness is quite remarkable.

The Mughuls of India developed a tradition where each ruler commissioned his own garden. Then, "At the owner's death the pavilion, generally placed in the center of the site, became the mausoleum, and the whole complex passed into the care of holy men."

The garden is as central to the concept of an Islamic home as the hearth is to the European home. It is interesting, then, that the hearth-fire in old traditions has a similar association with the life of the inhabitants of the house.

Commonly, the fire of the hearth was not allowed to go out. It was carefully covered with ashes each night at curfew so that a few selected embers would survive until morning. (In fact, the word "curfew" originated from the French word for cover-the-fire—couvre-feu.) Raglan comments that "the alarm and horror felt if the hearth-fire went out are out of all proportion to the inconvenience caused" by the need to relight it.

The connection between the life of the fire and the life of the inhabitant is also reflected in the custom of the housewarming ceremony. In contemporary America a housewarming party is given when a family moved into a new house. Perhaps all of the friends and their good wishes are thought to warm the house metaphorically. In traditional cultures, however, the warming is quite literal, for it involves the bringing in, or the first kindling, of the hearth fire, which then creates the proper spirit and sanctity to transform the house into a home.

We can easily imagine from our own experience why fire might be used as a symbol of the life of a house and the family that lives there. The fire was certainly the most lifelike element of the house: it consumed food and left behind waste; it could grow and move seemingly by its own will; and it could exhaust itself and die. And most important it was warm, one of the most fundamental qualities that we associate with our own lives. When the fire dies, its remains become cold, just as the body becomes cold when a person dies. Drawing a parallel to the concept of the soul that animates the physical body of the person, the fire, then, is the animating spirit for the body of the house.