A humidification system can include a heater base, a humidification chamber, and a breathing circuit. A cartridge can be removably coupled to the heater base. The cartridge can include various sensors, probes, sensor wire connectors, heater wire connectors, and/or other features. The cartridge can include features configured to mate with corresponding features on the humidification chamber and the heater base. The cartridge includes a memory, such as an EEPROM, or other suitable storage device. When the cartridge is installed on the heater base, the memory is electrically connected to a processor and/or memory of the heater base. Various models of cartridges can be produced for use with different humidification chambers, breathing circuits, and/or therapies. A connector can couple an inspiratory conduit to an outlet port of the humidification chamber. The connector can provide a pneumatic connection to the outlet port and an electrical connection to the cartridge.