I agree with the thermostat comment.
What I don't understand is why the thermostat allows a temperature drop when water/humidity is added, I have to go back to fifth grade text book, "I am not smarter than a fifth grader"! The answer must have something to do with wet bulb and evaporation.
edited for fifth grade grammar mistake.![]()
Still air with wafer thermostats are notably un reliable with temperature change.