In the emerging “Internet of Things” era, the traditional approach to humidity measurement using large-footprint legacy discrete circuits or bulky humidity sensing modules is no longer suitable to meet the demands for smaller, lighter and lower-power end products. This white paper talks about the benefits of using digital humidity sensors and what factors to consider when designing a humidity sensing system. This includes traditional discrete relative humidity (RH) sensors versus single-chip digital relative humidity sensor ICs, calculation of average power consumed for RH and temperature measurements, and choosing the optimal battery for a portable humidity sensing system.