what did u buy a humidifier for? a humidifier puts moisture into the air to where your plants can develope mold and other dieseases. and of course the temp will rise because your basically trying to mimic a tropical forest with that... if u do use it i suggest leaving it on for 2 hours and off for 9 hours and back on for 2 hours
Thats weird, my place gets dry in the winter, when not used, it will be 20% RH, when on it rises to 55%, just get a fan in there also dude, thats what i did
Cool mist is ultrasonic. I feel that humidification techniques can cause dehydration. When growing Salvia was still new and not really studied, my leaves grew much larger healthier, signs of better hydration without occasional misting. Spraying the leaves with water cause them to curl and be more brittle, I think that, depending on the humidification technique, causes capillary action to actually remove more water.... my place is ridiculously dry though.
Ultraonic, however, should be a safe choice. The water vapor is so small it's absorbed instantly into the plants (~4 nm water droplets!)
Also is clean as distilled. Considered a dry fog/mist. If used in aeroponics, only needs 25% usual nute dose, 50% max to prevent burning. A lot higher efficiency, with smaller rez and easier setup.