International Journal of Biometeorology

, Volume 56, Issue 1, pp 165–176 | Cite as

The perceived temperature – a versatile index for the assessment of the human thermal environment. Part A: scientific basics

  • Henning Staiger
  • Gudrun Laschewski
  • Angelika Grätz
Original Paper


The Perceived Temperature (PT) is an equivalent temperature based on a complete heat budget model of the human body. It has proved its suitability for numerous applications across a wide variety of scales from micro to global and is successfully used both in daily forecasts and climatological studies. PT is designed for staying outdoors and is defined as the air temperature of a reference environment in which the thermal perception would be the same as in the actual environment. The calculation is performed for a reference subject with an internal heat production of 135 W m−2 (who is walking at 4 km h−1 on flat ground). In the reference environment, the mean radiant temperature equals the air temperature and wind velocity is reduced to a slight draught. The water vapour pressure remains unchanged. Under warm/humid conditions, however, it is implicitly related to a relative humidity of 50%. Clothing is adapted in order to achieve thermal comfort. If this is impossible, cold or heat stress will occur, respectively. The assessment of thermal perception by means of PT is based on Fanger’s Predicted Mean Vote (PMV) together with additional model extensions taking account of stronger deviations from thermal neutrality. This is performed using a parameterisation based on a two-node model. In the cold, it allows the mean skin temperature to drop below the comfort value. In the heat, it assesses additionally the enthalpy of sweat-moistened skin and of wet clothes. PT has the advantages of being self-explanatory due to its deviation from air temperature and being—via PMV—directly linked to a thermo-physiologically-based scale of thermal perception that is widely used and has stood the test of time. This paper explains in detail the basic equations of the human heat budget and the coefficients of the parameterisations.


Equivalent temperature Thermal assessment Heat budget model Thermal perception 



The described parameterisations are based on the two-node model in the version of T. Kinouchi und M. Kanda, Tokyo Institute of Technology from 1998 provided by Prof. Dr A. Matzarakis, Albert-Ludwigs University Freiburg, Germany and in the version of ASHRAE (2001) provided by Prof. Dr R. de Dear, Macquarie University, Sydney, Australia. Thanks go to Dr. M. Nikolopoulou, Bath University, United Kingdom, who grants access to the RUROS database in the framework of the EU-COST-Action 730 on Universal Thermal Climate Index.


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Copyright information

© ISB 2011

Authors and Affiliations

  • Henning Staiger
    • 1
  • Gudrun Laschewski
    • 2
  • Angelika Grätz
    • 2
  1. 1.Deutscher Wetterdienst (emeritus)ElzachGermany
  2. 2.Deutscher WetterdienstFreiburgGermany

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