We used to have a humidifier attached to our central heating system. When I took it apart for cleaning I was grossed out by the calcium, lime and silt accumulated in there. Well, after a plumber coming in to help he said the unit was too old and he tossed it. I covered the hole with sheeet metal. Question: Do you think the humidifier is neccessary to help during the heating season. I notice a change in my allergies already.