This disclosure describes systems and methods for humidifying ventilator delivered breathing gases. These systems and methods utilize a hollow cone atomizer (e.g., a pressure swirl atomizer) and/or a heating element associated with a heating circuit and/or a heating tube. In some aspect, the systems and methods utilize received flow, temperature, and/or humidity information to determine an amount of water to add to breathing gases to reach a desired humidity of the breathing gases delivered to the patient. In further aspects, the humidification system can serve as a nebulization system for delivering nebulized medicine.