currently have a wood/oil combo forced air furnace in my basement. while the burning wood i am getting a smell of smoke in the house. chimney draft is good, not getting no back draft through the door while lighting or refilling. i have return air in main living area and one in the basement which is half complete. the area where the furnace is, is unfinished. The wood and oil share the same flue and chimney with non barometric damper. i am thinking it mabye something to do with negative pressure. any ideas or advice would be helpful. House is newly built with mabye 15 fires burnt in the furncae and it is not the smell of new coming from the furncae, it sticks to your clothes after so long. thanks