These are the steps I took (after reading quite a few posts in the HA Forum):-

  • Create a Derivative Helper with Precision = 2, Time window = 1 min, Time unit = Minutes and Max sub-interval = 5 mins
  • Create 3 Triggers:-
  • When Fan_Bathroom changes to On for 10:00
  • When Bathroom Humidity is above 80 for 5 seconds
  • When Bathroom Humidity Derivative is above 1
  • Create 3 Options:-
  • If triggered by Bathroom Humidity High
  • If triggered by Bathroom Humidity Derivative above limit
  • If triggered by Bathroom Fan On for 10 minutes

Notes:

  • The option to turn the fan off when triggered avoids the problem if a “delay” is used instead.