Defines the concept of nonuniformity of the hygrothermal microclimate (NUN) within a building as the condition of the hygrothermal constituent of a microenvironment that produces the physiologically and psychologically significant change of the heat load (thermal stress) on people either in space, in time or both together. Describes a new instrument for its estimation - the stereothermometer comprising a globe with a high-emissivity surface divided into six segments whose temperatures are termed stereotemperatures. Explains how the NUN can be calculated from their corresponding difference, and should be within the thermoregulatory range of the human body. Notes the advantages of the system.

KEYWORDS: Thermal comfort, measuring equipment, microclimate, instruments, buildings, temperature, humidity