Use of Humidifiers/Cool Mist or Warm?

I just know what I do.
A humidifier with UV light is supposed to kill most bacteria in the water before it goes into the vaporization chamber. So look for UV-C light in the description.
I use the water from my zero filter. Distilled would be good but it can become expensive and inconvenient.
A central HVAC dries out the air. In the winter, I turn it lower and control heat in the bedroom with an electric heater. I like an infrared/radiant panel or micathermic heater for this (no glowing elements or fan noise). I keep it pointed away from the bed, or it can get too warm to sleep!
In the summer our particular HVAC will keep it at 55% roughly when the temp is at 75-77. Then I usually don't have to use a humidifier, but a fan to circulate the air can make it more comfortable at those temps.
I use a CPAP but find it actually more convenient to use a humidifier, rather that the humidifier in the CPAP. You might be different. I don't know if a pulmonologist or sleep doctor might prescribe a CPAP just for humidification. I use it for sleep apnea.