The thermal index ETU (Universal effective temperature) was developed by Nagano and Horikoshi (2011a). This index can:

• Consider the solar radiation and heat conduction, as well as air temperature, longwave radiation, humidity, air velocity, metabolic rate, and clothing insulation, based on the human heat balance
• Indicate the universal and separate effects of the thermal factors simultaneously, in the same unit of degree Celsius °C
• Indicate the effects on local body area(s) as well as a whole body simultaneously, in the same unit of degree Celsius °C

The thermal index ETVO (Outdoor ETV) was developed by Nagano and Horikoshi (2011b). This index can:

• Consider the solar radiation, as well as air temperature, longwave radiation, humidity, air velocity, metabolic rate, and clothing insulation, based on the human heat balance
• Indicate the universal and separate effects of the thermal factors simultaneously, in the same unit of degree Celsius °C
• Indicate the effects on local body area(s) as well as a whole body simultaneously, in the same unit of degree Celsius °C