Effects of relative humidity on thermistor mount measurements

Thermistor mounts are served as transfer standards which are calibrated in microcalorimeter. A correlation between the effective efficiency of thermistor mount and the relative humidity of the laboratory has been observed. The difference of effective efficiency measurement in 20% and 50% humidity level can be about 9 times the k=1 uncertainty. The effects of humidity on thermistor mounts can result in the changes of effective efficiency. While the humidity impacts on other microwave device in microcalorimeter is not the main reason of these changes.