In the past we have given attention to the heating of our dwellings, offices and factories for the purpose of human comfort. In what now seems to us the "dark ages," this was considered a luxury rather than a necessity, as today. Similarly, in years to come, air conditioning and cooling for summer may become a necessity rather than a luxury, and we will look upon present times as marking the end of that "dark age" in which there was but relatively little cooling for human comfort.Opening page of “Air Conditioning—New Prospects for an Established Industry” by Willis H. Carrier in the May 1929 issue of Heating Piping and Air Conditioning.

The office skyscrapers of the future may find it preferable to dispense with windows and the street noises and dust which they admit, and avoid the great wastes in congested cities due to unoccupied courts and areaways now used for purposes of window ventilation and light. Sun-ray electric lighting may prove equally good and much more dependable than sunlight itself. Ventilation both in summer and winter can be made much better than outside conditions which at present permit either excessive dryness or an intolerable humidity within enclosures.