One listed in your link looks promising… Give ir a try in a rule. the forum is to help you develop a solution, not provide a complete one. You need to understand your system to properly maintain it.
The formula below approximates the heat index in degrees Fahrenheit, to within ±1.3 °F (0.7 °C). It is the result of a multivariate fit (temperature equal to or greater than 80 °F (27 °C) and relative humidity equal to or greater than 40%) to a model of the human body.[[1]](https://en.wikipedia.org/wiki/Heat_index#cite_note-SteadmanI-1)[[13]](https://en.wikipedia.org/wiki/Heat_index#cite_note-13) This equation reproduces the above NOAA National Weather Service table (except the values at 90 °F (32 °C) & 45%/70% relative humidity vary unrounded by less than ±1, respectively).
