Almost all manufacturers of temperature control chambers provide details in their technical specifications on temperature homogeneity and temperature stability.
For the testing of ovens and incubators, DIN 12880:2007-05 is applicable in Germany. Here, the test setup is regulated for determining these two parameters, for determining heating up times and cooling down times and to determine the recovery times after the door has been opened.
The temperature variation results from the temperature progression of those measurement points which display the largest temperature deviation over time. The temperature homogeneity, that is, the spatial temperature deviation, results from the difference between the two measurement points with the highest and lowest measured temperature value.
Picture credit: Memmert GmbH + Co. KG