Victor and Aladar Olgyay's thermoheliodon: Controlling climate to reduce climate control

Lisa Moffitt

Research output: Contribution to journalArticlepeer-review


Victor and Aladar Olgyay’s thermoheliodon was an elaborate domed apparatus including a dizzying array of environmental simulation devices such as a wind tunnel, heliotrope with motored 5000 watt bulb “sun”, temperature sensors, air conditioning units, and heating coils. Completed between 1955-1963, the device simulated exterior climatic conditions in order to predict interior building thermal performance, reflecting a number of emerging concerns regarding post-war suburban housing design in the United States. The Olgyays were the first to develop a systematic methodology, based on ‘bioclimatic’ building response, for designing housing that responds to regional climatic conditions. Ultimately untenable, the thermoheliodon is first presented as an analog to the ‘bioclimatic’ environmental design methodology outlined in Victor Olgyay’s 1963 Design with Climate, a canonical environmental design textbook that continues to inform sustainable design today. This paper presents the thermoheliodon as two models—the apparatus simulating environmental phenomena and the scaled architectural model—with two environmental targets—exterior environment and interior environment. This conception reflects the methodological tension between reconciling a dynamic exterior environment with an interior environment of thermo-stability. These two model/target conceptions meet at the point of failure of device, the perimeter of the architectural model tested within the thermoheliodon, which recorded both exterior and interior thermal conditions, and which failed to resolve material thermal scaling properties. This paper explores the thermoheliodon as representing two competing models of environmental design that persist today. The architectural model in the thermoheliodon presents a model of building predicated on climatic variability and building adaptation; the domed apparatus of the thermoheliodon reflects a model of total environmental control and climatic homogeneity.
Original languageEnglish
Pages (from-to)255-266
Journalarq: Architectural Research Quarterly
Issue number3
Publication statusPublished - 3 Jan 2020


  • environmental design
  • environmental model
  • thermoheliodon
  • Victor and Aladar Olgyay


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