I am a 39 year old with cf and have 2 humidifiers in my house, one in my bedroom and one downstairs. I bought warm mist ones with a UV bulb that kills any bacteria. That, in combination with weekly cleaning, kills 99% of bacteria/molds so it is safer for patients with cf. They are made by Slant Fin. I live in New England, and we have very dry winter air here. The humidifiers really help. Good luck!