I guess I wasn't clear. The dryer is a regular electrical dryer. It is the air vent that has been attached to the chimney of the oil furnace. I know that it should be vented to the outside of the house. I need to rectify it.It is mostly a fire hazard and there is also a risk of the moisture from the dryer becoming a problem for the chimney itself. How can I seal off the hole, who can do it, and how much will it cost?