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.
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.
Textbooks on water-system engineering state that supply mains are generally installed on the north side of the street in the Northern Hemisphere and on the south side in the Southern Hemisphere, so that the sun will warm them. In both hemispheres they are supposed to be on the east side of north-south streets, on the premise that the afternoon sun is warmer than the morning sun.
The predicted mean vote (PMV) was developed by Povl Ole Fanger at Kansas State University and the Technical University of Denmark as an empirical fit to the human sensation of thermal comfort. It was later adopted as an ISO standard. It predicts the average vote of a large group of people on the a seven-point thermal sensation scale where:
For others, perhaps especially those artists who worked with light and transparency and were involved in the birth of the Light and Space Movement, an immaculate surface is a prerequisite. Helen Pashgian explained this very clearly:
“On any of these works, if there is a scratch... that’s all you see. The point of it is not the finish at all – the point is being able to interact with the piece, whether it is inside or outside, to see into it, to see through it, to relate to it in those ways. But that’s why we need to deal with the finish, so we can deal with the piece on a much deeper level”.
The importance of a pristine surface calls for a very low tolerance to damage by the artists. The feeling is shared by Larry Bell:
“I don’t want you to see stains on the glass. I don’t want you to see fingerprints on the glass... I don’t want you to see anything except the light that’s reflected, absorbed, or transmitted”