I recently bought a floor standing humidifier, because the humidity can easily drop below 20% here in the winter, and it’s not possible to add a humidifier to the furnace. I have no complaints about its performance.
However, it does not have anything to indicate how much water is left in the tank. I can understand even a simple floating plastic bead in a tube would make the tank more complex and likely to leak, so I guess forgivable.
What it does do is show a letter on a seven segment LED display to indicate the tank has no water in it. For anyone who has ever been inside a car, what letter would you choose to display when a tank is empty?
No, it shows an “F”.