[Arnold...!].

ir conditioning as we know it, providing thermal comfort by mechanical methods, first appeared in buildings about a hundred years ago. The ability to control temperature, humidity and air purity made urban development possible in the most inhospitable of locations. Together with electric lighting, air conditioning also eliminated restrictions on plan form and fenestration that architects had been constrained to work under since antiquity. But how did architects and engineers respond to these opportunities? What effect did this have on buildings? And, were the occupants any more comfortable? These questions will be addressed in two articles reviewing the evolution of modern office building design and the impact of air conditioning. In this first article, the focus is on the period from the middle of the 19 century, when offices first emerged as a distinct category of building, to the advent of air conditioning in the 1930s. The design of early examples is reviewed, as well as the way architects attempted to provide cool comfort before air conditioning. Also addressed is the impact of air conditioning in terms of form and fenestration on office building design. The second article reviews the developments from the start of the post-World War II boom in air conditioning to the current state of the art.