A fireplace chimney can be a source of major heat and/or cooled air loss. An improperly sealed fireplace is equal to an open door in many respects. Sealing the fireplace, either temporarily or permanently, will lead to a reduction in heating and air conditioning costs.
Types of Seals
Sealing a fireplace typically refers to closing off the entry to the firebox with brick or a board. This essentially prevents cold air from flowing down the chimney flue and into your house. It also stops warm air from escaping through the flue. Other heat loss prevention methods that can reduce costs involve temporarily sealing off the chimney flue with rolled-up batt insulation or a fitted foam board.