A kit for coupling a container holding a liquid to a fluid path of a humidifier is disclosed. The kit includes a spike configured to pierce the container and to pass the liquid from the container to a vent through a tube. The vent is configured to vent gas from the liquid while retaining the liquid. The vent has a vent body including an inlet configured for coupling to the tube to receive the liquid from the tube and an outlet configured to pass the liquid to the humidifier. A cap opening is positioned to vent the gas. A filter is positioned over the cap opening to prevent the escape of the liquid therethrough. A cap is coupled to the vent body over the cap opening and has at least one opening therein to allow passage of gas from the opening to atmosphere.