I have had a musty odor smell in my house for a couple of weeks. It seems like it is coming from our heating vents. We had problems with tiny nats flying around. Our plumbing was out and said they were drain nats and filled our drains with this gel. They disappeared but now they are back. Could this smell and the drain nats be related. I have two small children and are concerned of the health because of this smell.

Sometimes it is called the dirty sock syndrome and that usually comes from a dirty A/C coil in the furnace area. You could also have a blocked plumbing vent or a partially restricted drain.