What is humidifier capacity, and how often will I need to refill my humidifier?

Humidifier capacity is the maximum amount of water the humidifier can hold at any one time, and varies from 0.5 to 6 gallons, depending on the size of the humidifier. Output is the maximum amount of water the humidifier can add into the environment per day, and nearly all humidifiers have a higher output than capacity. The frequency with which you will need to refill your humidifier depends on your humidifier's tank capacity relative to output, and the speed setting you select. If your humidifier has a 5 gallon output per day, and it has a holding capacity of 2.5 gallons, you will need to refill the humidifier every 12 hours in order to obtain the full possible 5 gallon maximum output per 24 hour period. The higher the tank capacity relative to the output, the less often you will need to refill the humidifier. In addition, you can go longer between refills if you run your humidifier on a lower speed, or if you do not run it constantly 24 hours per day.

How are humidifiers filled?

Most humidifiers have a removable water tank which is filled at a sink or bathtub and then placed onto the humidifier base. As the water in the base of the humidifier is used, more water from the tank will be released into the base. Some humidifiers have an automatic shut-off feature which will turn the humidifier off once the water needs to be refilled. There are also some humidifiers with a "top-fill" design, which eliminates the need for the removable water tank. With these humidifiers, you pour water directly into the top of the humidifier using a pitcher, cup, or any other water container. This can be helpful for those with arthritis or who may have trouble lifting and carrying a water tank.