I recently installed a fireplace insert and soon after my 3 month old son came down with the croup, which sounds like a raspy seal bark cough. He has been sick for a few weeks and the pediatrician thinks it may be related to the fireplace insert. Is there any correlation? The insert is new so all the gaskets are sealed. The only smoke we get in the house is during reloads. The humidity is kept between 40-50%. We set up a thermometer in his room that records the daily low & high temps as usually 65* & 75*. Could this daily temperature swing be the reason he is not getting better? Maybe we should stop burning for 4 days & see if it makes a difference. Have you ever heard of this happening? I don't want to be afraid of using our new insert.