What is the response time of a typical chilled mirror hygrometer?
The response time of the instrument depends on the dew point at which it is operating. At dew points above 0 C, it has about a 15 second 68% response to a step change. Below 0 C, the instrument measures frost point, and the response is slower, mainly because of the outgassing characteristics of the sampling lines, and the reduced availability of water vapor for the deposit.