Currently it is possible to use calculated statistic value in Equation and Formula Smart Rules.

In Variables section, select device and pick one of its predefined statistic values:

Equation: Turn on vent if humidity in bathroom is 10% higher than in other room#

Variables:

Hu Humidity in bathroom - Average by hours

Hu1 Humidity in other room - Actual value

Equation:

(Hu - Hu1) > 0.1

Action:

Vent → Turn on