The best replacement for humidistat is hygrometer.

The best alternatives to humidistat are rated as following:
★★★★★  hygrometer
★  hygrostat

Your alternative for humidistat is not listed? Suggest!
Speaking about humidistat, one probably shouldn't forget about thermostat.

Other search terms related to humidistat and their ratings are:
★★★★★ thermostat
★ attic fan
★ bathroom fan
You have in mind a companion for humidistat and it is not yet here? Propose!



Google Trends

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humidistat
hygrometer
hygrostat