Evaporation rate

Every year we go through the same thing. The house gets too dry from the wood stove before we get the humidifiers going. You think I would remember this from feeding the fish every day. The water level on the side of the aquarium goes down at least one half an inch a day. So every weekend I'm filling it up to the top again. In the meantime we come down with that dry cough that just gives you a headache.