I'm new to the forum, and I thought maybe some of you would be more knowledgeable than I am on this issue and be able to help out. I apologize in advance for the length of my post! (o:

My wife and I recently bought a new home. The home was built this year and finished in June.. we moved in late September. Absolutely love the place, but having some issues with the furnace and smells.

I have asthma and pretty severe allergies and my wife has allergies as well.

Now that the weather has gotten cold we have a neighbor who has been burning every night and it smokes up the neighborhood. The problem for me is that smoke comes into our home (worse some nights than others) and it causes me a lot of asthma problems. I did a lot of research and went out and bought a new furnace filter. Our furnace had a standard 16X25X1 filter in it, and I replaced it with a 3M Filtrete 1900 allergy reduction filter.

This filter seems to reduce the amount of smoke smell that comes into the home, but in the past few days we have a strange smell coming out of all our registers when the heat is on. It smells like sawdust/new wood and basically like our basement smelled when we first moved here. The dusty smell comes through all the registers when the heat is on and it is making both my wife and I sick. My wife is having sore throats when she is home (feels fine when away from the house). I am constantly having itchy eyes, sneezing, etc.

Basically, my question is this. When I had been running the heat without any smell why would it all at once start putting out this sawdust/basement smell? I thought it could be the new filter so I took it out and put the old one back in, but that hasn't helped yet at least (it's only been one day). I considered cleaning all the ducts, but it seems strange to have to clean the ducts when the house is less than 6 months old.

Anyone with any insight as to what could cause this? Anything that can be done to test to see where the problem might be? Thanks in advance for the help!