Wood stove inserts fit mostly inside of the fireplace. They consist of a shell that lines the inside of the fireplace and a glass door that can close the fireplace as well. Wood stove inserts keep heat from escaping through the masonry of the fireplace. The lining provides and extra layer between the fire and the hearth that keeps the hot air in the house. The glass door can keep heat in the fireplace when the fireplace is in use or it can keep heat in the house when there is no fire present.
Wood stove inserts make fireplaces more heat efficient.
They prevent heat loss through the masonry, allowing the heat to warm up the house. Many wood stove inserts have small, unobtrusive electric fans that blow the warm air out into the surrounding room rather than letting it stay in the hearth. The glass door that covers the fireplace opening can keep heat that is already in the house from escaping up the flue when the fireplace is not in use.
Fireplaces with inserts are easier to clean than open fireplaces. The floors of the inserts are straight and flat, allowing people to simply sweep or scoop up any ash or dust. Also, the door can keep any soot from being blown out onto the floor surrounding the fireplace.